23 Oct
2009
23 Oct
'09
4:52 a.m.
Hi folks,
I'm currently checking out some TU56 DECTape drives. Stuck motors, burnt
electronics, dirt, and other issues usually come my way.
And broken indicator lights. Does anybody have experience replacing
those bulbs? Originally there are those white plastic blocks that should
be replaced as one piece. Nice idea - I have ONE complete replacement
and at least 6 to repair. Those blocks are easily opened, fiddling a new
lamp inside is easy and no problem. So what I ask you is only for ideas
about the right lamps to use. It should look similar to the original
lamps (or could be a bit brighter).
Some blasphemy to add:
If I don't find a quick solution, I'll fit one of the TU56s with crazy
colored LEDs. That might be considered a sacrilege by some people, but
it's quite reversible and non-destructive. I have LEDs in two RK05
drives, too (They're soldered to their series resistors and plugged in
like the original lamps, so everything can be reverted instantly). The
read and write indicators are quite more interesting that way (with
incandescent lamps you don't even see many accesses!).
But at the moment the question is for incandescent lamps. So please
share your ideas/experience with me!
Best wishes,
Philipp :-)
23 Oct
23 Oct
6:55 a.m.
----------------------------------------
Date: Fri, 23 Oct 2009 13:52:40 +0200
From: hachti at hachti.de
To:
Subject: TU56 lamp replacement
Hi folks,
I'm currently checking out some TU56 DECTape drives. Stuck motors, burnt
electronics, dirt, and other issues usually come my way.
And broken indicator lights. Does anybody have experience replacing
those bulbs? Originally there are those white plastic blocks that
---snip---
Hi
Measure one in operation. Check both the current and the
voltage. Don't just measure the ohms when off. Lamps
( At least modern lamps ) tend to be constant current
like and won't give you accurate reading when off.
Dwight
_________________________________________________________________
Windows 7: It helps you do more. Explore Windows 7.
http://www.microsoft.com/Windows/windows-7/default.aspx?ocid=PID24727::T:WL…
9:40 a.m.
And broken indicator lights. Does anybody have
experience replacing
those bulbs? Originally there are those white plastic blocks that
should be replaced as one piece. Nice idea - I have ONE complete
replacement and at least 6 to repair.
That prompted an interesting line of research. Those are apparently
DEC part number 12-09637, which in turn is a "Line-o-Lite" 3590A20.
Here's a picture of one, but they are sold out:
http://www.surplusshed.com/pages/item/m2255.html
http://www.surplusshed.com/photo.cfm?ID=M2255_1
They are a 12V indicator assembly made by Industrial Devices, Inc.
I haven't found a supplier for them yet. Looks like the newer
rectangular indicators are all smaller.
Those blocks are easily opened, fiddling a new
lamp inside is easy and no problem. So what I ask you is only for ideas
about the right lamps to use. It should look similar to the original
lamps (or could be a bit brighter).
Since the series resistor is 15 ohms, 1/4 watt, we can infer a maximum
current of about 100ma for the bulb. More than that would run the
resistor way too hot. I'd probably look for something in the 12-15V
range with a 60ma or less current draw (<=1W), and the desired brightness.
Vince
10:19 a.m.
On Fri, Oct 23, 2009 at 12:40 PM, Vincent Slyngstad <vrs at msn.com> wrote:
Nice find; shame they are sold out. I'd buy 10 in a heartbeat at
those prices (I have more than one drive to keep happy).
I myself will probably go the route of an LED replacement, but it's
always good to know what the incandescent options are.
Thanks, Vince!
-ethan
And broken
indicator lights. Does anybody have experience replacing those
bulbs? Originally there are those white plastic blocks that should be
replaced as one piece.
That prompted an interesting line of research. ?Those are apparently DEC
part number 12-09637, which in turn is a "Line-o-Lite" 3590A20.
Here's a picture of one, but they are sold out:
http://www.surplusshed.com/pages/item/m2255.html
http://www.surplusshed.com/photo.cfm?ID=M2255_1
24 Oct
24 Oct
2:19 p.m.
From: "Ethan Dicks":
On Fri, Oct 23, 2009 at 12:40 PM, Vincent Slyngstad
wrote:
Yeah, me too :-(.
That prompted an interesting line of research.
Those are apparently
DEC part number 12-09637, which in turn is a "Line-o-Lite" 3590A20.
Here's a picture of one, but they are sold out:
http://www.surplusshed.com/pages/item/m2255.html
http://www.surplusshed.com/photo.cfm?ID=M2255_1
Nice find; shame they are sold out. I'd buy 10 in a heartbeat at
those prices (I have more than one drive to keep happy). I myself will probably go the route of an LED
replacement, but it's
always good to know what the incandescent options are.
I also found this: http://www.pdp8.net/tu56/tu56.shtml
in which Dave G. describes a successful use of the CM2182 (14V,
80ma) bulb in this application. There don't seem to be many
low current bulb choices -- the CM2174 perhaps, but it's only
about 1/3 as bright, and only about 1/4 as long-lasting.
Thanks, Vince!
No problem!
Vince
23 Oct
23 Oct
9:41 a.m.
On Fri, 23 Oct 2009 13:52:40 +0200
Philipp Hachtmann <hachti at hachti.de> wrote:
Some blasphemy to add:
If I don't find a quick solution, I'll fit one of the TU56s with crazy
colored LEDs. That might be considered a sacrilege by some people, but
it's quite reversible and non-destructive.
This would be a sacrilege only if
your aim is a 100% original
restoration. If you just want to _repair_ a machine to get it back to
live, hell, LEDs are perfect. I have no problem if modern replacements
are used in old machines when original replacement parts are
unavailable. I have no problems with new parts even when they are
simply used to "enhance" old machines. (E.g. SMPSU instead a linear
regulator or newer disk drives to save power.)
E.g. I have fited SGI Indogos with ATX PSUs. The original PSUs die like
flies and are a nightmare to repair.
Or fans: If a fan fails, would you really looking for an exact
replacement? Most likely you will replace it with a generic fan, as
long as voltage and air throughput match. Same for indicator lamps.
They are generic components that emit light. I don't care if they are
LED or incandescent lamps, as long as they do the job.
--
tsch??,
Jochen
Homepage: http://www.unixag-kl.fh-kl.de/~jkunz/
25 Oct
25 Oct
3:35 p.m.
Hi Jochen,
This would be a sacrilege only if your aim is a 100%
original
restoration. If you just want to _repair_ a machine to get it back to
live, hell, LEDs are perfect. I have no problem if modern replacements
are used in old machines when original replacement parts are
unavailable. I have no problems with new parts even when they are
simply used to "enhance" old machines. (E.g. SMPSU instead a linear
regulator or newer disk drives to save power.)
I usually deliberately add new parts
to old machines to get them going.
But I'm reluctant with respect to irreversible upgrading stuff.
The LED/incandescent question is in fact a question of taste. And I
prefer the incandescent variant in most cases. The TU56 has those huge
glowing fields... And I think it would be nicer to have incandescent
light there. At least in most of the units...
E.g. I have fited SGI Indogos with ATX PSUs. The
original PSUs die like
flies and are a nightmare to repair.
That's fine, I find. I fitted a HP7978
tape drive with an AT power
supply - just had to solder all the wires to readily available holes in
the backplane. And the original PSU (it sometimes did not start) and all
possibilities to repair it were kept.
Or fans: If a fan fails, would you really looking for
an exact
replacement? Most likely you will replace it with a generic fan, as
long as voltage and air throughput match.
Of course! But fans are always generic
stuff.
Same for indicator lamps.
They are generic components that emit light. I don't care if they are
LED or incandescent lamps, as long as they do the job.
Yes, but they do the job
differently. And it's a question of aesthetic
value one should keep in mind.
Regards,
Philipp
26 Oct
26 Oct
12:14 p.m.
Or fans: If a
fan fails, would you really looking for an exact
replacement? Most likely you will replace it with a generic fan, as
long as voltage and air throughput match.
Of course! But fans are always generic
stuff. 
12:42 p.m.
On Monday 26 October 2009, Tony Duell wrote:
I guess I am the only person here who _repairs_ fans. I've been known
to rewind the stator, and replace components on the control PCB.
-tony
Tony,
Personally, I'm surprised that you haven't repaired incandescent light
bulbs... or maybe you have?
Pat
--
Purdue University Research Computing --- http://www.rcac.purdue.edu/
The Computer Refuge --- http://computer-refuge.org
Or fans: If a fan fails, would you really looking for
an exact
replacement? Most likely you will replace it with a generic fan,
as long as voltage and air throughput match.
Of course! But fans are always generic stuff. 
3:24 p.m.
-----Original Message-----
From: cctalk-bounces at classiccmp.org [mailto:cctalk-
bounces at classiccmp.org] On Behalf Of Philipp Hachtmann
Sent: Monday, October 26, 2009 1:17 PM
To: On-Topic and Off-Topic Posts
Subject: Re: TU56 lamp replacement
This was once somewhat common. Some of the CRTs made for high-end oscilloscopes were so
complex that it was fiscally prudent to replace the filament when it burned out. -- Ian
Personally, I'm surprised that you haven't repaired incandescent
light
bulbs... or maybe you have?
I once found
some info about people who repaired CRT tubes...!!
:-)
10:56 p.m.
This was once somewhat common. ?Some of the CRTs made
for high-end oscilloscopes were so complex that it was fiscally prudent to replace the
filament when it burned out. ?-- Ian
Common TV CRTs were also rebuilt in the 1950s.
Earlier this year I sold some 4CX50000s to a power tube rebuilder, and
he gave a nickel tour of his plant. Very cool - he could (and did)
take apart a number of scrap tubes, use the parts, and make a good one
out of the pile.
On a related note, I am in need of a 21M44P31A tube for a Cyber
console. Tube rebuilding is not an option, as the phosphor has been
splotched due to the breaking of the neck.
--
Will
27 Oct
27 Oct
2:14 p.m.
Personally, I'm surprised that you haven't repaired incandescent light
bulbs... or maybe you have?
I once found some info about people who repaired CRT
tubes...!!
2:06 p.m.
Personally, I'm surprised that you haven't
repaired incandescent light
bulbs... or maybe you have?
I have -- sort of :-)
More seriously, I was repairing an HP59306 relay actuator. This unit has
some 'midget flange' bulbs in the pushbutton switches, and I couldn't
find a supplier who woul sell 1-offs in the UK (a couple had failed).
However, I did have some wire-ended bulbs of suitable voltage and
current.
So I took the old midget flange bulb and cracked the glass part out with
pliers. Desoldered the wires from the side of the cap and the base
contact, and cleaned out the inside of the cap.. Then inserted a
wire-ended bulb and soldered it in place.
The result is a 'repaired' midget flange bulb that fits the HP switchbank
with no modifications.
-tony
5:44 p.m.
On 27/10/2009 21:06, Tony Duell wrote:
> Personally, I'm surprised that you haven't
repaired incandescent light
> bulbs... or maybe you have?
So I took the old midget flange bulb and cracked the
glass part out with
pliers. Desoldered the wires from the side of the cap and the base
contact, and cleaned out the inside of the cap.. Then inserted a
wire-ended bulb and soldered it in place.
I once "repaired" bulbs too, for a set of nice outdoor Christmas lights
where I couldn't get the right decorative bulbs. They're the kind that
have an outer glass envelope over the actual "bulb" containing the
filament. I bought new plain lamps with the same base and rating, and
took some of the ones that had burnt out, cut the envelopes off using a
diamond scriber, and epoxied the old outers over the new plain lamps.
Amazing what you (think you) can do when you're bored.
--
Pete Peter Turnbull
Network Manager
University of York
6:39 p.m.
Chuck Guzis wrote:
On 28 Oct 2009 at 0:44, Pete Turnbull wrote:
I thought that was Pre 1900's there. Tubes ( triodes )were mostly understood
by then. I am using 45 tubes and they came out 1929 or so.
Pentodes came out in the 1930's. Radar in 1940's
and Electronic Brains[1] 1950's.
Amazing what you (think you) can do when
you're bored.
There's a guy on the web who makes his own (cold cathode) CRTs.
We're basically talking 1920's technology here, aren't we? --Chuck
[1] Now back on topic.
7:32 p.m.
Triodes? 1907, Lee de Forest.
________________________________________
From: cctalk-bounces at classiccmp.org [cctalk-bounces at classiccmp.org] On Behalf Of Ben
[bfranchuk at jetnet.ab.ca]
Sent: Tuesday, October 27, 2009 6:39 PM
To: On-Topic and Off-Topic Posts
Subject: Re: TU56 lamp replacement
Chuck Guzis wrote:
On 28 Oct 2009 at 0:44, Pete Turnbull wrote:
I thought that was Pre 1900's there. Tubes ( triodes )were mostly understood
by then. I am using 45 tubes and they came out 1929 or so.
Pentodes came out in the 1930's. Radar in 1940's
and Electronic Brains[1] 1950's.
Amazing what you (think you) can do when
you're bored.
There's a guy on the web who makes his own (cold cathode) CRTs.
We're basically talking 1920's technology here, aren't we? --Chuck
[1] Now back on topic.
27 Oct
27 Oct
2:11 p.m.
I guess I am the only person here who _repairs_
fans. I've been known to
rewind the stator, and replace components on the control PCB.
Oh! What about the
bearings?!? That's the most usual source of failure...
5316
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19 comments
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participants (12)
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ard＠p850ug1.demon.co.uk -
bfranchuk＠jetnet.ab.ca -
cclist＠sydex.com -
dkelvey＠hotmail.com -
ethan.dicks＠gmail.com -
hachti＠hachti.de -
IanK＠vulcan.com -
jkunz＠unixag-kl.fh-kl.de -
pat＠computer-refuge.org -
pete＠dunnington.plus.com -
vrs＠msn.com -
wdonzelli＠gmail.com