22 Aug
2013
22 Aug
'13
3:04 p.m.
I have a DEQNA cabinet kit that does not work. I know this because if I
replace it with another one the activity light on the switch works and I am
able to see MOP requests coming from the machine to my boot node, with the
faulty one none of this happens.
Now, I have tested the fuse and I have tested the connectivity of every wire
from the internal connector that connects to the DEQNA
board (also tried
with a DELQA by the way) to the AUI connector on the outside of
the cabinet
kit. Everything seems to be OK. But it doesn't work. I have tried
"jiggling"
the wires a bit while testing the continuity of the wires, but it still
seems OK.
What other failures could there be?
Regards
Rob
22 Aug
22 Aug
3:42 p.m.
I have a DEQNA cabinet kit that does not work. [...]
Now, I have tested the fuse and I have tested the
connectivity of
every wire from the internal connector that connects to the DEQNA
board (also tried with a DELQA by the way) to the AUI connector on
the outside of the cabinet kit. Everything seems to be OK. But it
doesn't work.
What other failures could there be?
Depending on how you checked continuity, it occurs to me that one of
the two connectors might not be making a good connection with its
mating connector. For example, if a dirty mating surface gives the
+12V (I think it is) power pin ten ohms or so of series resistance, you
might not notice that if (a) your continuity tester considers that to
be good continuity (depends on the tool and, maybe, how you used it) or
(b) your test used a different surface on connector from the one that
matters when connecting to the board (clean end versus dirty face, for
example). But ten ohms, if the transceiver wants to pull (say) half an
amp, means five volts of drop, quite likely enough to break it.
Or, if the AUI socket on the cab kit has a contact that's pushed too
far into its housing, sticking a wire in there to check continuity may
well work, but the mating pin connector not reach.
There are other failure modes, but they all strike as far less likely
in this case. For example, I once extended AUI with something like
25 feet of 15-pin ribbon cable; it semi-worked, but produced lots of
errors. (I was trying to overextend it. I actually wanted to use
about eight inches of the same ribbon cable, and which worked fine.
This led me to get curious just how tolerant it was.) But in a cab kit
the wires from board connector to back panel are unlikely to be
non-original.
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23 Aug
23 Aug
1:18 p.m.
I have a DEQNA cabinet kit that does not work. I know this because if I
replace it with another one the activity light on the switch works and I am
able to see MOP requests coming from the machine to my boot node, with the
faulty one none of this happens.
I asusme the 2 cabkits are of the same type,. there's not some differnece
between them
Now, I have tested the fuse and I have tested the connectivity of every wire
from the internal connector that connects to the DEQNA board (also tried
with a DELQA by the way) to the AUI connector on the outside of the cabinet
kit. Everything seems to be OK. But it doesn't work. I have tried
"jiggling"
the wires a bit while testing the continuity of the wires, but it still
seems OK.
IIRC there is a ltitle electronics in these cabkits, something like a
linear voltae regualtor to provide the power for the transceiver. Is it
possible that this has failed. Have yuo measured the votlage ebtween the
transceiver power ins on the AUI connector using both the good and bad
cabkits (with the machine powered up, of course)?
-tony
4:04 p.m.
At 04:18 PM 8/23/2013, Tony Duell wrote:
IIRC there is a ltitle electronics in these cabkits,
something like a
linear voltae regualtor to provide the power for the transceiver. Is it
possible that this has failed. Have yuo measured the votlage ebtween the
transceiver power ins on the AUI connector using both the good and bad
cabkits (with the machine powered up, of course)?
No, those cabkits are entirely passive. The voltage supply for the
transceiver is regulated on the board and fuse protected.
-Rick
24 Aug
24 Aug
11:42 a.m.
At 04:18 PM 8/23/2013, Tony Duell wrote:
Yes, you're right (of course). As a 'Unibus man'[1] I am familiar wit hte
DEUNA cabkit and incorrectly assuemd the DEQNA one would be the same. The
DEUNA cabkit does have a little circuitry on it, according to the
printset it's an inrush current limiter. Quite why that's needed on
Unibus machnes and not Qbus ones I don't know.
[1] SOme Unibus machines have real front panels and CPUs built from
simple ICs I can understand and can still easily buy. Qbus macbines
don't.
-tony
IIRC there is a ltitle electronics in these
cabkits, something like a
linear voltae regualtor to provide the power for the transceiver. Is it
possible that this has failed. Have yuo measured the votlage ebtween the
transceiver power ins on the AUI connector using both the good and bad
cabkits (with the machine powered up, of course)?
No, those cabkits are entirely passive. The voltage supply for the
transceiver is regulated on the board and fuse protected. 
23 Aug
23 Aug
6:24 p.m.
On Aug 23, 2013, at 4:18 PM, ard at p850ug1.demon.co.uk (Tony Duell) wrote:
IIRC there is a ltitle electronics in these cabkits,
something like a
linear voltae regualtor to provide the power for the transceiver. Is it
possible that this has failed. Have yuo measured the votlage ebtween the
transceiver power ins on the AUI connector using both the good and bad
cabkits (with the machine powered up, of course)?
Unless I'm grossly mistaken, the only thing that's even close to being
called electronics on the cab kit is a fuse. It is otherwise just
wires (inasmuch as a fuse is not a wire).
My money is on a bad receptacle pin socket. Have you tried plugging
in an unpopulated DA15 plug (solder cup type) and checking the
continuity with that?
- Dave
24 Aug
24 Aug
12:32 a.m.
-----Original Message-----
From: cctalk-bounces at classiccmp.org [mailto:cctalk-
bounces at classiccmp.org] On Behalf Of David Riley
Sent: 24 August 2013 02:24
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Re: DEQNA/DELQA cabinet kit fault mystery
On Aug 23, 2013, at 4:18 PM, ard at p850ug1.demon.co.uk (Tony Duell) wrote:
called
IIRC there is a ltitle electronics in these
cabkits, something like a
linear voltae regualtor to provide the power for the transceiver. Is
it possible that this has failed. Have yuo measured the votlage
ebtween the transceiver power ins on the AUI connector using both the
good and bad cabkits (with the machine powered up, of course)?
Unless I'm grossly mistaken, the only thing that's even close to being
electronics on the cab kit is a fuse. It is otherwise
just wires
(inasmuch as a
fuse is not a wire).
Indeed, there are no active components, just a fuse. The kit is entirely
passive.
My money is on a bad receptacle pin socket. Have you
tried plugging in an
unpopulated DA15 plug (solder cup type) and checking the continuity with
that?
- Dave
This is the avenue I am going to pursue. This cab kit used to work, but it
has stopped working. I will just have to find a DA15 plug to test with.
Regards
Rob
10:55 a.m.
-----Original Message-----
From: cctalk-bounces at classiccmp.org [mailto:cctalk-
bounces at classiccmp.org] On Behalf Of Robert Jarratt
Sent: 24 August 2013 08:32
To: 'General Discussion: On-Topic and Off-Topic Posts'
Subject: RE: DEQNA/DELQA cabinet kit fault mystery
called
has
-----Original Message-----
From: cctalk-bounces at classiccmp.org [mailto:cctalk-
bounces at classiccmp.org] On Behalf Of David Riley
Sent: 24 August 2013 02:24
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Re: DEQNA/DELQA cabinet kit fault mystery
On Aug 23, 2013, at 4:18 PM, ard at p850ug1.demon.co.uk (Tony Duell)
wrote:
IIRC there is a ltitle electronics in these
cabkits, something like
a linear voltae regualtor to provide the power for the transceiver.
Is it possible that this has failed. Have yuo measured the votlage
ebtween the transceiver power ins on the AUI connector using both
the good and bad cabkits (with the machine powered up, of course)?
Unless I'm grossly mistaken, the only thing that's even close to being electronics on the cab kit is a fuse. It is
otherwise just wires
(inasmuch as a
fuse is not a wire).
Indeed, there are no active components, just a fuse. The kit is entirely
passive.
My money is on a bad receptacle pin socket. Have
you tried plugging
in an unpopulated DA15 plug (solder cup type) and checking the
continuity with that?
- Dave
This is the avenue I am going to pursue. This cab kit used to work, but it stopped working. I will just have to find a DA15 plug
to test with.
Regards
Rob
Even more mysterious now. I got a DA15 plug and tested it plugged into the
cabinet kit socket. Continuity was fine. So I decided to test the other side
of the cable, at the connector that plugs into the DEQNA, using a card edge
connector I have lying around. That too was fine.
Either the plug and card edge connectors I used make better contact than the
DEQNA and the AUI converter, or the problem has temporarily gone away. I
should note that I tried the same cabinet kit with a DELQA, so I have tested
that side of the kit with two cards, and I have also tested it with two
different AUI converters.
I will have to try putting it back on the DEQNA and see if it works, and
perhaps test the outputs with it actually connected.
Regards
Rob
11:51 a.m.
Unless I'm grossly mistaken, the only thing
that's even close to being
You're right. The prints (for one of the Qbus ethernate cards) are on
Bitsavers, and that shows the cabkit.
called electronics on the cab kit is a fuse. It is
otherwise just
wires (inasmuch as a fuse is not a wire).
Bad fuseholder? :-)
My money is on a bad receptacle pin socket. Have you tried plugging
in an unpopulated DA15 plug (solder cup type) and checking the
continuity with that?
The printset seems ot show that the DA15 socket is one of those with
indiidualt contacts crimped to the wires and then inserted into the
hosuing. I have had problems with those where contacts have slid out
again when you stick the plug in, leading to bad connections. It is worth
_gnetilly_ pulling each wire at the back of the socket to see if any come
free.
Other than that, yes, stick a DA15 pug in and make sure the pins actually
do end up conencted to the right wires.
-tony
23 Aug
23 Aug
4:02 p.m.
At 06:04 PM 8/22/2013, Robert Jarratt wrote:
I have a DEQNA cabinet kit that does not work. I know
this because if I
replace it with another one the activity light on the switch works and
I am
able to see MOP requests coming from the machine to my boot node, with the
faulty one none of this happens.
Now, I have tested the fuse and I have tested the connectivity of
every wire
from the internal connector that connects to the DEQNA board (also tried
with a DELQA by the way) to the AUI connector on the outside of the
cabinet
kit. Everything seems to be OK. But it doesn't work. I have tried
"jiggling"
the wires a bit while testing the continuity of the wires, but it still
seems OK.
What other failures could there be?
Have you verified that someone hasn't mixed up the pins on the Berg
header that plugs in to the board?
Other than a blown fuse, that's about all that can go wrong with these
- some kind of mechanical problem.
-Rick
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9 comments
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participants (5)
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ard＠p850ug1.demon.co.uk -
fraveydank＠gmail.com -
mouse＠Rodents-Montreal.ORG -
rick＠rickmurphy.net -
robert.jarratt＠ntlworld.com