2 Mar
2015
2 Mar
'15
5:48 a.m.
Well, i desolder the LB1620... it has obvious signs of burning under
the chips and also on the pcb.
I saw the smoke coming from that place but I thought it came from one
of cap of 2700pf instead came from the chip.
The short circuit between +24vdc and the ground is gone out.
+24vdc go just at pin 4 of the LB1620.
+24vdc to R112 and the D102 Zener that is saved so from here to pins: 19, 2
and 12 of the LB1620 then it continue to pin 16 of the TC9142P.
The datasheet of this last one say that the power voltage would be between
5Vdc and 9,5Vdc. So would this say that the zenere has to be from
5 to 9 vdc? Have i to measure the exact voltage on pin 16 of the TC9142P
without the LB1620 and how have i to expect?
The LB1620 is smoked. What other components must be tested to ensure
that the new LB1620 can not be broken just fitted?
Thanks a lot.
E.
--------- Original Message --------
Da: "General Discussion: On-Topic Posts" <cctech at
classiccmp.org>
To: "General Discussion: On-Topic Posts" <cctech at
classiccmp.org>
Oggetto: Re: How to save two Mitsubishi M2896 drive (spindle motor smoked!)
Data: 02/03/15 04:20
Indeed, pin 4 (Vcc1) should be +24V, this is for the motor windings drive.
You need to look at pin 19 (Vcc2) of the LB1620 or the voltage across zener
D102.
Follow the pcb trace from the junction of R112 and D102, goes to pin 19,
looks like pins 9 & 2 as well, and on to supply the other ICs.
On 2015-Mar-01, at 1:38 PM, Enrico Lazzerini wrote:
>
> Mhmhm... i checked the pcb. The LB1620 pin 4 is wired to the pin on
which I
> think comes +24vdc... so... let me check what could happens before.
Could
> happens that is it broken something and it goes to this little pcb
+24vdc
> instead of 12-15vdc???
>
> I misured the voltage coming to this pcb and over there is +24VDC
> This explain well the why this pcb smoke and it is hot.
>
>
> Enrico
>
> -----Messaggio originale-----
> Da: cctech [mailto:cctech-bounces at classiccmp.org] Per conto di Brent
Hilpert
> Inviato: domenica 1 marzo 2015 22:08
> A: General Discussion: On-Topic Posts
> Oggetto: Re: How to save two Mitsubishi M2896 drive (spindle motor
smoked!)
>
>
> On 2015-Mar-01, at 9:56 AM, Enrico Lazzerini wrote:
>
>> Thanks Tony for your suggestions. What I means is:
>>
>> It happen in two distinct times every time when I used the drive
to read
>> through a PC with the software IMD to create images of floppy
disks 8 ".
> Not
>> having the correct power connectors i power the drives in this
way: + 5vdc
>> and ground coming by a PC power supply and +24vdc and ground from
a
> Chinese
>> power supply. I must have certainly reversed this last one even
for a few
>> seconds exchange +24vdc with the ground. Now both spindle motor
supplied
>> also with only +24vdc start smoking in the vicinity of the chip
LB1620 and
>> cause of cooling you can not touch it as hot it is. If I try to
measure
> the
>> resistance between pins +24vdc and ground of each spindle motor
drive i
> get
>> 1327ohm on FD0 while i measure 19ohm on the spindle motor drive
FD1. There
>> are no visible damage nor to the components nor the PCB wires.
>> In both pcbs anyway the chips LB1620 sunburnt from not being able
to keep
> a
>> finger on it.
>> I searched on ebay and the only place that has LB1620 seems to be:
>>
>
http://www.ebay.it/itm/LB1620-INTEGRATED-CIRCUIT-IC-BOX-74-/390955452872?pt=
>> LH_DefaultDomain_0&hash=item5b06c2c9c8
>>
>> The input's pins of the pcb are : +24vdc, ground, and the rest
could be a
>> control.
>>
>> The point is that I have no experience on these components.
>> Replace the chip could make it burn again for my inexperience.
>>
>
> I notice in one of the photos you have written 15V for the zener D102,
and
> on both boards they look like they have been replaced.
>
> D102 and R112 are a simple regulator to reduce the +24V down for the
chip
> supplies (looking at the photos to trace the circuit).
> +24 is otherwise used directly only for the motor windings, in part
via Vcc1
> on the LB1620.
>
> The LB1620 datasheet specifies the Vcc2 range for the 1620 to be only
8.5 to
> 14V, not 15V.
>
> Check the Vcc2/zener level to see whether the zeners are good and what
> voltage they are.
> I expect Vcc2 (and the zener V) is supposed to be 12V or 9V.
>
--
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2 Mar
2 Mar
7:50 a.m.
Well, i desolder the LB1620... it has obvious signs of burning under
the chips and also on the pcb.
OK... That is a likely result of getting the power connections the wrong way round.
To answer a question you asked in another message. I've never seen a socket for this
chip
and I think you need to solder it in directly so the metal heatsink bracket will fit
properly.
[..]
+24vdc to R112 and the D102 Zener that is saved so
from here to pins: 19, 2
and 12 of the LB1620 then it continue to pin 16 of the TC9142P.
The datasheet of this last one say that the power voltage would be between
5Vdc and 9,5Vdc. So would this say that the zenere has to be from
5 to 9 vdc? Have i to measure the exact voltage on pin 16 of the TC9142P
without the LB1620 and how have i to expect?
Yes. Connect up the 24V supply now and measure the voltage across the zener D102. It
should be, I guess ,between 5V and 9.5V.
The LB1620 is smoked. What other components
must be tested to ensure
that the new LB1620 can not be broken just fitted?
Check that zener voltage. If that's OK, it is very likely nothing will damage the new
IC.
Thanks a lot.
-tpmy
E.
--------- Original Message --------
Da: "General Discussion: On-Topic Posts" <cctech at
classiccmp.org>
To: "General Discussion: On-Topic Posts" <cctech at
classiccmp.org>
Oggetto: Re: How to save two Mitsubishi M2896 drive (spindle motor smoked!)
Data: 02/03/15 04:20
Indeed, pin 4 (Vcc1) should be +24V, this is for the motor windings drive.
You need to look at pin 19 (Vcc2) of the LB1620 or the voltage across zener
D102.
Follow the pcb trace from the junction of R112 and D102, goes to pin 19,
looks like pins 9 & 2 as well, and on to supply the other ICs.
On 2015-Mar-01, at 1:38 PM, Enrico Lazzerini wrote:
>
> Mhmhm... i checked the pcb. The LB1620 pin 4 is wired to the pin on
which I
> think comes +24vdc... so... let me check what could happens before.
Could
> happens that is it broken something and it goes to this little pcb
+24vdc
> instead of 12-15vdc???
>
> I misured the voltage coming to this pcb and over there is +24VDC
> This explain well the why this pcb smoke and it is hot.
>
>
> Enrico
>
> -----Messaggio originale-----
> Da: cctech [mailto:cctech-bounces at classiccmp.org] Per conto di Brent
Hilpert
> Inviato: domenica 1 marzo 2015 22:08
> A: General Discussion: On-Topic Posts
> Oggetto: Re: How to save two Mitsubishi M2896 drive (spindle motor
smoked!)
>
>
> On 2015-Mar-01, at 9:56 AM, Enrico Lazzerini wrote:
>
>> Thanks Tony for your suggestions. What I means is:
>>
>> It happen in two distinct times every time when I used the drive
to read
>> through a PC with the software IMD to create images of floppy
disks 8 ".
> Not
>> having the correct power connectors i power the drives in this
way: + 5vdc
>> and ground coming by a PC power supply and +24vdc and ground from
a
> Chinese
>> power supply. I must have certainly reversed this last one even
for a few
>> seconds exchange +24vdc with the ground. Now both spindle motor
supplied
>> also with only +24vdc start smoking in the vicinity of the chip
LB1620 and
>> cause of cooling you can not touch it as hot it is. If I try to
measure
> the
>> resistance between pins +24vdc and ground of each spindle motor
drive i
> get
>> 1327ohm on FD0 while i measure 19ohm on the spindle motor drive
FD1. There
>> are no visible damage nor to the components nor the PCB wires.
>> In both pcbs anyway the chips LB1620 sunburnt from not being able
to keep
> a
>> finger on it.
>> I searched on ebay and the only place that has LB1620 seems to be:
>>
>
http://www.ebay.it/itm/LB1620-INTEGRATED-CIRCUIT-IC-BOX-74-/390955452872?pt=
>> LH_DefaultDomain_0&hash=item5b06c2c9c8
>>
>> The input's pins of the pcb are : +24vdc, ground, and the rest
could be a
>> control.
>>
>> The point is that I have no experience on these components.
>> Replace the chip could make it burn again for my inexperience.
>>
>
> I notice in one of the photos you have written 15V for the zener D102,
and
> on both boards they look like they have been replaced.
>
> D102 and R112 are a simple regulator to reduce the +24V down for the
chip
> supplies (looking at the photos to trace the circuit).
> +24 is otherwise used directly only for the motor windings, in part
via Vcc1
> on the LB1620.
>
> The LB1620 datasheet specifies the Vcc2 range for the 1620 to be only
8.5 to
> 14V, not 15V.
>
> Check the Vcc2/zener level to see whether the zeners are good and what
> voltage they are.
> I expect Vcc2 (and the zener V) is supposed to be 12V or 9V.
>
--
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12:58 p.m.
On 2015-Mar-02, at 7:50 AM, tony duell wrote:
Lazzerini wrote:
The 1620 min Vcc2 was 8.5V, so with the max 9.5V of the 9142, it looks like the zener is
supposed to be 9V (9.1V).
One concern is that if the zener is incorrect and too high a V, and the short in the 1620
was pulling that V down, the shorted 1620 may have been saving the other semiconductors.
Powering it up with the 1620 now removed might apply high V to the other semis, so it
would be an idea to isolate them for testing the zener voltage, or remove the zener for
out-of-circuit checking (apply a voltage to it though a series R).
I'm just going by your writing in one of the photos that it's a 15V zener - how
did you know that or come to write it?
> +24vdc to R112 and the D102 Zener that is saved so
from here to pins: 19, 2
> and 12 of the LB1620 then it continue to pin 16 of the TC9142P.
The D102-zener-regulated supply, in addition to supplying the 1620 & 9142, appears to
supply that other 8-pin chip, and the hall-effect sensors.
The datasheet
of this last one say that the power voltage would be between
5Vdc and 9,5Vdc. So would this say that the zenere has to be from
5 to 9 vdc? Have i to measure the exact voltage on pin 16 of the TC9142P
without the LB1620 and how have i to expect?
Yes. Connect up the 24V supply now and measure the voltage across the zener D102. It
should be, I guess ,between 5V and 9.5V. The LB1620 is
smoked. What other components must be tested to ensure
that the new LB1620 can not be broken just fitted?
Check that zener voltage. If that's OK, it is very likely nothing will damage the new
IC.
1:17 p.m.
New subject: R: How to save two Mitsubishi M2896 drive (spindle motor smoked!)
Connecting the bigger resistors and the zener D102 the voltage on this last
one is 12,45Vdc. This one is direct connected to:
LB1620 pins 9,12,19
TC9142P pins 4,12,16
C358C pin 8
Then LB1620 pin 4 = +24Vdc
Is in this way that TC9142P could be burned?
Enrico
-----Messaggio originale-----
Da: tony duell [mailto:ard at p850ug1.demon.co.uk]
Inviato: luned? 2 marzo 2015 16:50
A: Enrico Lazzerini; General Discussion: On-Topic Posts
Oggetto: RE: How to save two Mitsubishi M2896 drive (spindle motor smoked!)
Well, i desolder the LB1620... it has obvious signs of burning under
the chips and also on the pcb.
OK... That is a likely result of getting the power connections the wrong way
round.
To answer a question you asked in another message. I've never seen a socket
for this chip
and I think you need to solder it in directly so the metal heatsink bracket
will fit properly.
[..]
+24vdc to R112 and the D102 Zener that is saved so
from here to pins: 19,
2
and 12 of the LB1620 then it continue to pin 16 of the
TC9142P.
The datasheet of this last one say that the power voltage would be between
5Vdc and 9,5Vdc. So would this say that the zenere has to be
from
5 to 9 vdc? Have i to measure the exact voltage on pin
16 of the TC9142P
without the LB1620 and how have i to expect?
Yes. Connect up the 24V supply now and measure the voltage across the zener
D102. It
should be, I guess ,between 5V and 9.5V.
The LB1620 is smoked. What other components
must be tested to ensure
that the new LB1620 can not be broken just fitted?
Check that zener voltage. If that's OK, it is very likely nothing will
damage the new IC.
Thanks a lot.
-tpmy
E.
--------- Original Message --------
Da: "General Discussion: On-Topic Posts" <cctech at
classiccmp.org>
To: "General Discussion: On-Topic Posts" <cctech at
classiccmp.org>
Oggetto: Re: How to save two Mitsubishi M2896 drive (spindle motor smoked!)
Data: 02/03/15 04:20
Indeed, pin 4 (Vcc1) should be +24V, this is for the motor windings drive.
You need to look at pin 19 (Vcc2) of the LB1620 or the voltage across zener
D102.
Follow the pcb trace from the junction of R112 and D102, goes to pin 19,
looks like pins 9 & 2 as well, and on to supply the other ICs.
On 2015-Mar-01, at 1:38 PM, Enrico Lazzerini wrote:
>
> Mhmhm... i checked the pcb. The LB1620 pin 4 is wired to the pin on
which I
> think comes +24vdc... so... let me check what could happens before.
Could
> happens that is it broken something and it goes to this little pcb
+24vdc
> instead of 12-15vdc???
>
> I misured the voltage coming to this pcb and over there is +24VDC
> This explain well the why this pcb smoke and it is hot.
>
>
> Enrico
>
> -----Messaggio originale-----
> Da: cctech [mailto:cctech-bounces at classiccmp.org] Per conto di Brent
Hilpert
> Inviato: domenica 1 marzo 2015 22:08
> A: General Discussion: On-Topic Posts
> Oggetto: Re: How to save two Mitsubishi M2896 drive (spindle motor
smoked!)
>
>
> On 2015-Mar-01, at 9:56 AM, Enrico Lazzerini wrote:
>
>> Thanks Tony for your suggestions. What I means is:
>>
>> It happen in two distinct times every time when I used the drive
to read
>> through a PC with the software IMD to create images of floppy
disks 8 ".
> Not
>> having the correct power connectors i power the drives in this
way: + 5vdc
>> and ground coming by a PC power supply and +24vdc and ground from
a
> Chinese
>> power supply. I must have certainly reversed this last one even
for a few
>> seconds exchange +24vdc with the ground. Now both spindle motor
supplied
>> also with only +24vdc start smoking in the vicinity of the chip
LB1620 and
>> cause of cooling you can not touch it as hot it is. If I try to
measure
> the
>> resistance between pins +24vdc and ground of each spindle motor
drive i
> get
>> 1327ohm on FD0 while i measure 19ohm on the spindle motor drive
FD1. There
>> are no visible damage nor to the components nor the PCB wires.
>> In both pcbs anyway the chips LB1620 sunburnt from not being able
to keep
> a
>> finger on it.
>> I searched on ebay and the only place that has LB1620 seems to be:
>>
>
http://www.ebay.it/itm/LB1620-INTEGRATED-CIRCUIT-IC-BOX-74-/390955452872?pt=
>> LH_DefaultDomain_0&hash=item5b06c2c9c8
>>
>> The input's pins of the pcb are : +24vdc, ground, and the rest
could be a
>> control.
>>
>> The point is that I have no experience on these components.
>> Replace the chip could make it burn again for my inexperience.
>>
>
> I notice in one of the photos you have written 15V for the zener D102,
and
> on both boards they look like they have been replaced.
>
> D102 and R112 are a simple regulator to reduce the +24V down for the
chip
> supplies (looking at the photos to trace the circuit).
> +24 is otherwise used directly only for the motor windings, in part
via Vcc1
> on the LB1620.
>
> The LB1620 datasheet specifies the Vcc2 range for the 1620 to be only
8.5 to
> 14V, not 15V.
>
> Check the Vcc2/zener level to see whether the zeners are good and what
> voltage they are.
> I expect Vcc2 (and the zener V) is supposed to be 12V or 9V.
>
--
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=
1:39 p.m.
On 2015-Mar-02, at 1:17 PM, Enrico Lazzerini wrote:
Connecting the bigger resistors and the zener D102 the
voltage on this last
one is 12,45Vdc. This one is direct connected to:
LB1620 pins 9,12,19
TC9142P pins 4,12,16
C358C pin 8
Then LB1620 pin 4 = +24Vdc
Is in this way that TC9142P could be burned?
Well it is excessive, so you wouldn't want to run it at that level for long periods.
Whether it (the 9142) has failed already is an open question.
Did you test the zener and big R together out-of-circuit, or with the other ICs still
connected?
12.45V sounds low for a 15V zener (if that's what it is), so I wonder if something
else is pulling the V down.
I hope the hall sensors are OK, I don't know how much variation on supply V they can
tolerate.
3 Mar
3 Mar
11 a.m.
New subject: R: How to save two Mitsubishi M2896 drive (spindle motor smoked!)
Well, on the zener i measured 12,45V. So it is a 12V I think. Not 15V as I
previous supposed. It power the pins as I written so :
About powers:
LB1612 pin 19 datasheet says 8-14VDC
TC1642P pin 16 datasheet says 5-9.5VDC
C358C pin 8 datasheet says until +32vdc
I could try to substitute the zener with a 7808 ic 1W.
This could keep all is not warm and protect. RIGHT?
ENrico
1:41 p.m.
On 2015-Mar-03, at 11:00 AM, Enrico Lazzerini wrote:
Well, on the zener i measured 12,45V. So it is a 12V I
think. Not 15V as I
previous supposed. It power the pins as I written so :
About powers:
LB1612 pin 19 datasheet says 8-14VDC
TC1642P pin 16 datasheet says 5-9.5VDC
C358C pin 8 datasheet says until +32vdc
I could try to substitute the zener with a 7808 ic 1W.
This could keep all is not warm and protect. RIGHT?
8V of a 7808 may be low/marginal for the 8.5V min specified in the LB1620 datasheet (at
least in the Sanyo one I'm looking at).
You could add a diode or two in series with the GND leg of the 7808 to raise the voltage
to around 8.6V (1 diode) or 9.2V (2 diodes).
(cathode to GND, ordinary 1N400x for example).
2:25 p.m.
New subject: R: How to save two Mitsubishi M2896 drive (spindle motor smoked!)
I thought to this with a 7808:
https://www.dropbox.com/s/ekj0bftrh86nhsa/PowerOK.jpg?dl=0
to test before to resolder the new LB1620.
Thanks for the kind support of all of you.
Enrico
-----Messaggio originale-----
Da: cctalk [mailto:cctalk-bounces at classiccmp.org] Per conto di Brent Hilpert
Inviato: marted? 3 marzo 2015 22:41
A: General Discussion: On-Topic and Off-Topic Posts
Oggetto: Re: How to save two Mitsubishi M2896 drive (spindle motor smoked!)
On 2015-Mar-03, at 11:00 AM, Enrico Lazzerini wrote:
Well, on the zener i measured 12,45V. So it is a 12V I
think. Not 15V as I
previous supposed. It power the pins as I written so :
About powers:
LB1612 pin 19 datasheet says 8-14VDC
TC1642P pin 16 datasheet says 5-9.5VDC
C358C pin 8 datasheet says until +32vdc
I could try to substitute the zener with a 7808 ic 1W.
This could keep all is not warm and protect. RIGHT?
8V of a 7808 may be low/marginal for the 8.5V min specified in the LB1620
datasheet (at least in the Sanyo one I'm looking at).
You could add a diode or two in series with the GND leg of the 7808 to raise
the voltage to around 8.6V (1 diode) or 9.2V (2 diodes).
(cathode to GND, ordinary 1N400x for example).=
2:49 p.m.
On 2015-Mar-03, at 11:00 AM, Enrico Lazzerini wrote:
> Well, on the zener i measured 12,45V. So it is a 12V I think. Not 15V as I
> previous supposed. It power the pins as I written so :
>
> About powers:
> LB1612 pin 19 datasheet says 8-14VDC
> TC1642P pin 16 datasheet says 5-9.5VDC
> C358C pin 8 datasheet says until +32vdc
>
> I could try to substitute the zener with a 7808 ic 1W.
> This could keep all is not warm and protect. RIGHT?
Brent wrote:
8V of a 7808 may be low/marginal for the 8.5V min
specified in the LB1620
datasheet (at least in the Sanyo one I'm looking at).
You could add a diode or two in series with the GND leg of the 7808 to raise
the voltage to around 8.6V (1 diode) or 9.2V (2 diodes).
(cathode to GND, ordinary 1N400x for example).=
On 2015-Mar-03, at 2:25 PM, Enrico Lazzerini wrote:
I thought to this with a 7808:
https://www.dropbox.com/s/ekj0bftrh86nhsa/PowerOK.jpg?dl=0
to test before to resolder the new LB1620.
Thanks for the kind support of all of you.
Enrico
If you cut where you indicate and install the 7808 across that point, you will miss the
supply point for the hall-effect sensors, they would still be supplied by the higher zener
V (note R109 that takes off around the R112-D102 junction to head to the sensors).
Rather than cutting the trace, I would just remove R112 & D102 and install the 7808
across the former R112 opening, with the aforementioned diode(s) in the GND leg.
There's enough copper there you may be able to drill a new hole or two to catch the
7808 legs.
(Alternatively, 9.1V zeners are pretty common.)
4 Mar
4 Mar
2:22 p.m.
New subject: R: How to save two Mitsubishi M2896 drive (spindle motor smoked!)
Sorry Brent, did you means like this pic?
https://www.dropbox.com/s/z5pj6lgbjos70fj/PowerSAFE.jpg?dl=0
Enrico
-----Messaggio originale-----
Da: cctech [mailto:cctech-bounces at classiccmp.org] Per conto di Brent Hilpert
Inviato: marted? 3 marzo 2015 23:49
A: General Discussion: On-Topic and Off-Topic Posts
Oggetto: Re: How to save two Mitsubishi M2896 drive (spindle motor smoked!)
On 2015-Mar-03, at 11:00 AM, Enrico Lazzerini wrote:
> Well, on the zener i measured 12,45V. So it is a 12V I think. Not 15V as
I
> previous supposed. It power the pins as I written
so :
>
> About powers:
> LB1612 pin 19 datasheet says 8-14VDC
> TC1642P pin 16 datasheet says 5-9.5VDC
> C358C pin 8 datasheet says until +32vdc
>
> I could try to substitute the zener with a 7808 ic 1W.
> This could keep all is not warm and protect. RIGHT?
Brent wrote:
8V of a 7808 may be low/marginal for the 8.5V min
specified in the LB1620
datasheet (at least in the Sanyo one I'm looking at).
You could add a diode or two in series with the GND leg of the 7808 to
raise
the voltage to around 8.6V (1 diode) or 9.2V (2
diodes).
(cathode to GND, ordinary 1N400x for example).=
On 2015-Mar-03, at 2:25 PM, Enrico Lazzerini wrote:
I thought to this with a 7808:
https://www.dropbox.com/s/ekj0bftrh86nhsa/PowerOK.jpg?dl=0
to test before to resolder the new LB1620.
Thanks for the kind support of all of you.
Enrico
If you cut where you indicate and install the 7808 across that point, you
will miss the supply point for the hall-effect sensors, they would still be
supplied by the higher zener V (note R109 that takes off around the
R112-D102 junction to head to the sensors).
Rather than cutting the trace, I would just remove R112 & D102 and install
the 7808 across the former R112 opening, with the aforementioned diode(s) in
the GND leg. There's enough copper there you may be able to drill a new hole
or two to catch the 7808 legs.
(Alternatively, 9.1V zeners are pretty common.)
2:36 p.m.
On 2015-Mar-04, at 2:22 PM, Enrico Lazzerini wrote:
Sorry Brent, did you means like this pic?
https://www.dropbox.com/s/z5pj6lgbjos70fj/PowerSAFE.jpg?dl=0
Yes.
I take it you found a 7809 instead of 7808, great.
17 Mar
17 Mar
4:08 p.m.
New subject: R: How to save two Mitsubishi M2896 drive (spindle motor smoked!)
Dear All,
I wish to update about my work. I received finally a couple of LB1620 from
Arizona. Italian custom got them for a lot of time. Well I desoldered it
from the pcb and I checked between +24vdc and ground
for not have any
shortcircuit. Good thing. I algo put away the circuit with a
resistor and a
zener diode and insert a new 7809 ic to give a good power of 9vdc to pins:
19,9 and 12 of the lb1620. powering with +24vdc the spindle motor its not
rotate. As you can see from the its pics from here:
https://www.dropbox.com/sh/p12w71v69tjgfz7/AAAIReql4Se5ZCkLClPoAVOPa?dl=0
there is a tirdh input pin in the connector: what is it use? Is goes to pin5
of the C358C as input of the operational IC. On each pin of the engine I
misured a +4,6 vdc respect to the gnd.
I have also a scope but what have I to checK?
Thanks so much for any suggestion.
Enrico
5:56 p.m.
On 2015-Mar-17, at 4:08 PM, Enrico Lazzerini wrote:
I wish to update about my work. I received finally a
couple of LB1620 from
Arizona. Italian custom got them for a lot of time. Well I desoldered it
from the pcb and I checked between +24vdc and ground for not have any
shortcircuit. Good thing. I algo put away the circuit with a resistor and a
zener diode and insert a new 7809 ic to give a good power of 9vdc to pins:
19,9 and 12 of the lb1620. powering with +24vdc the spindle motor its not
rotate. As you can see from the its pics from here:
https://www.dropbox.com/sh/p12w71v69tjgfz7/AAAIReql4Se5ZCkLClPoAVOPa?dl=0
there is a tirdh input pin in the connector: what is it use? Is goes to pin5
of the C358C as input of the operational IC. On each pin of the engine I
misured a +4,6 vdc respect to the gnd.
I have also a scope but what have I to checK?
Looking at your photos, I think I can trace the 3rd connector pin to (LM358).5 as you say,
the other input looks like it comes from a voltage divider, the output looks like it goes
to a transistor and then on to (TL9142).11, which from the datasheet is the play/stop
control. So it looks like that 3rd pin is a motor on/off input, using an op-amp as
comparator for sensing the control input. You could try pulling the 3rd connector pin up
to +5V through a (say) 10K limiting resistor, to see if it turns on, but we won't
really know what the trip voltage is without knowing the voltage divider resistor values.
If you'd like continued assistance, I have to ask you to take a couple of
better-resolution photos of the top and bottom of the board(s), so we can make a decent
schematic. Then we might be able to figure out some voltages or signals to test for, to
check whether any of the other semiconductors were damaged by the previous bad voltages.
I'm also curious about D101 - is it really a diode? it sort of looks like a resistor
in the photo - and what is the color code? From tracing it looks like it raises the GND
leg of the 9142 IC, which would lower the supply voltage to that IC.
18 Mar
18 Mar
2:05 p.m.
New subject: R: How to save two Mitsubishi M2896 drive (spindle motor smoked!)
I tried to connect a resistor of 10kohm to 3rd wire of the connector but
putting it to ground or to +5vdc nothing happens. I also checked if with a
disk inserted into the drive what kind of signal come out from the 3rd wire
from the main but always remains at zero volts.
Checking with the
oscilloscope signals on chips of the spindle motor all seems very
stop and
static. I report below some value of voltages misured on the IC's pin and
photos at high resolution at the link below.
https://www.dropbox.com/sh/ozy5mn06hyz9jn1/AADelz2vVsTSEAwmwoVzvwppa?dl=0
LB1620
Pin1= 18,2V
Pin2= 9,2V
Pin3=0V
Pin4=24v
Pin5=pin6=pin7=0V
Pin8=0V
Pin9=pin19=8,93V
TC9142P
pin1= pin5= Q101Base=3,52v
pin4= pin10= pin16=8,93v
pin6=6,2v
pin7=pin8=3,5v
pin9= NC =3,52v
pin11= Q101collector = 8,97v
pin12= pin13= NC
pin14= pin15= square wave
C358C
pin1=pin2=pin3= 4,5v
pin4=GND
pin5=0,5v connected to the 3rd input wire
pin6= 1,2v connected to the r101 - r105 with the other side of r101
connected to pin 16 of 9142
pin7= 7,76v connected to Q101 collector
pin8= 9v
main link with other info
https://www.dropbox.com/sh/p12w71v69tjgfz7/AAAIReql4Se5ZCkLClPoAVOPa?dl=0
Thanks in advance for your help.
Enrico
3:02 p.m.
On 2015-Mar-18, at 2:05 PM, Enrico Lazzerini wrote:
I tried to connect a resistor of 10kohm to 3rd wire of
the connector but
putting it to ground or to +5vdc nothing happens. I also checked if with a
disk inserted into the drive what kind of signal come out from the 3rd wire
from the main but always remains at zero volts. Checking with the
oscilloscope signals on chips of the spindle motor all seems very stop and
static. I report below some value of voltages misured on the IC's pin and
photos at high resolution at the link below.
https://www.dropbox.com/sh/ozy5mn06hyz9jn1/AADelz2vVsTSEAwmwoVzvwppa?dl=0
This directory is currently empty, at least as I see it here.
LB1620
Pin1= 18,2V
Pin2= 9,2V
Pin3=0V
Pin4=24v
Pin5=pin6=pin7=0V
Pin8=0V
Pin9=pin19=8,93V
TC9142P
pin1= pin5= Q101Base=3,52v
pin4= pin10= pin16=8,93v
pin6=6,2v
pin7=pin8=3,5v
pin9= NC =3,52v
pin11= Q101collector = 8,97v
pin12= pin13= NC
pin14= pin15= square wave
C358C
pin1=pin2=pin3= 4,5v
pin4=GND
pin5=0,5v connected to the 3rd input wire
pin6= 1,2v connected to the r101 - r105 with the other side of r101
connected to pin 16 of 9142
pin7= 7,76v connected to Q101 collector
pin8= 9v
Haven't been through them thoroughly yet but most of these look sensible.
Presence of the square wave on (TC9142)pin14,15 is a good sign, that's the reference
oscillator, and suggests the 9142 may be OK.
- Observe (C358)pin7 while alternating the 0/+5 test voltage on the 3rd connector pin, pin
7 should change accordingly to 0V & 9V. Similarly (LB1620)pin11 should be changing.
- The hall sensors may still be suspect. They are supplied by being stacked in series with
two resistors, one each in the ground leg side and +9V supply side. First thing to do
would be to measure the V on the two supply pins of each hall sensor (the pins closer to
the motor center). The supply voltage should divided between the 3 sensors and 2
resistors.
The halls sensors feed the LB1620 with a differential drive from each sensor to avoid
having to make a fixed GND reference, which allowed them to be stacked in series for the
supply. In theory you would be able to observe a change on one of the drive pair of each
sensor with the scope as you manually rotate the rotor but the change may be too small to
observe within the bias from the stacked supply. Properly one would use two scope channels
in A-B difference mode to observe the drive pair.
- Instead, or in addition, you might try watching the (LB1620)pins1,2,3 outputs while
spinning the rotor manually to see if they change.
main link with other info
https://www.dropbox.com/sh/p12w71v69tjgfz7/AAAIReql4Se5ZCkLClPoAVOPa?dl=0
19 Mar
19 Mar
11:36 a.m.
New subject: R: How to save two Mitsubishi M2896 drive (spindle motor smoked!)
Well the verifications taken here:
- Observe (C358)pin7 while alternating the 0/+5 test voltage on the 3rd
connector pin, pin 7 should change accordingly to 0V & 9V. => NO it remain
statically at 7,76V
- Similarly (LB1620)pin11 should be changing. => NO it remain at 3,44V
- The hall sensors may still be suspect. They are supplied by being stacked
in series with two resistors, one each in the ground leg side and +9V supply
side. First thing to do would be to measure the V on the two supply pins of
each hall sensor (the pins closer to the motor center). The supply voltage
should divided between the 3 sensors and 2 resistors.
=> The chain is :
- from the +5vdc to R109 = 6,76V
- then from R109 to the 1st hall sensor = 5,17V
- then from the 1st hall sensor to the 2nd hall sensor = 3,62V
- then from the 3rd hall sensor / R110 to the gnd = 2,2v
So at each hall sensor we have (potential difference):
1st = 1.59V
2nd = 1.55v
3rd = 1.42v
The halls sensors feed the LB1620 with a differential drive from each sensor
to avoid having to make a fixed GND reference, which allowed them to be
stacked in series for the supply. In theory you would be able to observe a
change on one of the drive pair of each sensor with the scope as you
manually rotate the rotor but the change may be too small to observe within
the bias from the stacked supply. Properly one would use two scope channels
in A-B difference mode to observe the drive pair.
=> confirm that rotating the motor my voltmeter change a bit its measured
value
- Instead, or in addition, you might try watching the (LB1620)pins1,2,3
outputs while spinning the rotor manually to see if they change.
=> confirm that rotating the motor my voltmeter change a bit its measured
value
Could at this point the problem to be on c358c or the transistor q101?
Enrico
2:43 p.m.
See schematic:
http://www3.telus.net/~bhilpert/tmp/mitsubishi8fdd.pdf
On 2015-Mar-19, at 11:36 AM, Enrico Lazzerini wrote:
Well the verifications taken here:
- Observe (C358)pin7 while alternating the 0/+5 test voltage on the 3rd
connector pin, pin 7 should change accordingly to 0V & 9V. => NO it remain
statically at 7,76V
- Similarly (LB1620)pin11 should be changing. => NO it remain at 3,44V
- The hall sensors may still be suspect. They are
supplied by being stacked
in series with two resistors, one each in the ground leg side and +9V supply
side. First thing to do would be to measure the V on the two supply pins of
each hall sensor (the pins closer to the motor center). The supply voltage
should divided between the 3 sensors and 2 resistors.
=> The chain is :
- from the +5vdc to R109 = 6,76V
- then from R109 to the 1st hall sensor = 5,17V
- then from the 1st hall sensor to the 2nd hall sensor = 3,62V
- then from the 3rd hall sensor / R110 to the gnd = 2,2v
So at each hall sensor we have (potential difference):
1st = 1.59V
2nd = 1.55v
3rd = 1.42v
This may be a concern. We don't know just what hall-effect sensors are being used but
I found a datasheet for functionally similar 4-pin sensors.
The specs may of course be different, but the supply voltage range in that datasheet is
2.2-12V with 3.25-5mA current.
From calculations, operating at 9V, I was wondering if
the voltage drop across the resistors left what may be too low a voltage on each sensor.
Recall we concluded the regulator voltage would be 9V because that fit inbetween the
limits of the 9142 and 1620 specs. However we now know the 9142 GND is raised by 3.5V,
lowering the supply to that IC.
Ii may be the regulator voltage is supposed to be 12V rather than 9. This would give:
- 12V for the 1620, within spec,
- 12-3.5=8.5V for the 9142, within spec,
- and raise the voltage across each hall sensor.
The halls sensors feed the LB1620 with a differential
drive from each sensor
to avoid having to make a fixed GND reference, which allowed them to be
stacked in series for the supply. In theory you would be able to observe a
change on one of the drive pair of each sensor with the scope as you
manually rotate the rotor but the change may be too small to observe within
the bias from the stacked supply. Properly one would use two scope channels
in A-B difference mode to observe the drive pair.
=> confirm that rotating the motor my voltmeter change a bit its measured
value
How much (voltage change)?
- Instead, or in addition, you might try watching the
(LB1620)pins1,2,3
outputs while spinning the rotor manually to see if they change.
=> confirm that rotating the motor my voltmeter change a bit its measured
value
Could at this point the problem to be on c358c or the transistor q101?
The 358 could be a concern, or the diode at location R117, or Q101.
R117 looks like it was supposed to be a pull-down resistor but was installed with a diode
as a reverse-bias clamp instead, for who knows what reason.
You could try removing Q101, then with the limiting resistor feeding the 3rd connector
pin, watch what happens to (LM358)pin7 while toggling the control voltage into the
limiting resistor. But also watch what happens at (LM358)pin5 to ensure it changes. The
concern is that the R117 diode, if damaged/shorted, could be clamping the input voltage to
the op amp comparator.
Expected operation of the 358 half with pin 7 open (Q101 removed):
pin 5 pin 6 pin 7
------ ------ ------
0V 1.25V ~ 0V
1.25V 1.25V ~ 9V
Also with Q101 removed, you could try connecting (LC9142)pin11 to pin 1 (see 9142
datasheet). If the motor still doesn't run it may be time to consider changing the
voltage regulator to 12V.
4 p.m.
New subject: R: How to save two Mitsubishi M2896 drive (spindle motor smoked!)
I desoldered Q101 and i reconnect the 12v zener D102 and the resistor R112
and I measured those voltages on 358:
1=6,32v
2=6,37v
3=6,36v
4=0v
5=0,74v
6=1,752v
7=11,49v
8=12,7v
Have I to resolder just the q101 now?
Enrico
20 Mar
20 Mar
12:22 a.m.
On 2015-Mar-19, at 4:00 PM, Enrico Lazzerini wrote:
I desoldered Q101 and i reconnect the 12v zener D102
and the resistor R112
and I measured those voltages on 358:
1=6,32v
2=6,37v
3=6,36v
4=0v
5=0,74v
6=1,752v
7=11,49v
8=12,7v
Have I to resolder just the q101 now?
It looks like the 358 is faulty, but you should try pulling pin 5 high/low while watching
pin 7 again - see last part of my previous message. Also the bit about pulling the 9142
pin 11 to pin 1.
12:26 p.m.
New subject: R: How to save two Mitsubishi M2896 drive (spindle motor smoked!)
IT WORKS!!! IT WORKS!!! AGAIN!!!!!
Thanks BRENT!!!! Thanks for the schematics.
Well the problem were 3 solders. After to insert the D102 zener (maybe
12,5V) and the resistor R112 (180ohm) on their position it I set the 3rd
wire to the ground, the pin7 of c358c change its level. I reconnect also the
transistor Q101. The spindle motor do not want to work.
I remember that pin 1,2 and 3 were soldered even on the component side of
the PCB so I would wanted to try to solder them again: the spindle motor
begun to rotate. What emotion!!!!
I not know if it rotate at the correct speed cause I have to rebuild on a
table my old pc an to connect the 8" drive to see if with IMD software I
will can to read a 8" floppy disk correctly, but at this moment the spindle
motor works again!!
Thanks A lot
Enrico
6:41 p.m.
On 2015-Mar-20, at 12:26 PM, Enrico Lazzerini wrote:
IT WORKS!!! IT WORKS!!! AGAIN!!!!!
Thanks BRENT!!!! Thanks for the schematics.
Well the problem were 3 solders. After to insert the D102 zener (maybe
12,5V) and the resistor R112 (180ohm) on their position it I set the 3rd
wire to the ground, the pin7 of c358c change its level. I reconnect also the
transistor Q101. The spindle motor do not want to work.
I remember that pin 1,2 and 3 were soldered even on the component side of
the PCB so I would wanted to try to solder them again: the spindle motor
begun to rotate. What emotion!!!!
I not know if it rotate at the correct speed cause I have to rebuild on a
table my old pc an to connect the 8" drive to see if with IMD software I
will can to read a 8" floppy disk correctly, but at this moment the spindle
motor works again!!
Great; if the 3rd-pin motor control does work then the 358 is likely OK and the speed
regulation (that uses the other half of the 358) is likely good as well.
3516
days inactive
3535
days old
20 comments
3 participants
participants (3)
-
ard＠p850ug1.demon.co.uk -
enrico.lazzerini＠email.it -
hilpert＠cs.ubc.ca