7 Apr
2017
7 Apr
'17
11:47 a.m.
Hi all --
I recently got insanely lucky and scored a Straight-8 (S/N 14). It made it
in nearly one piece from Ohio, but during transit, all of the G603 Memory
Selector Matrix boards fell out. It looks like on early revisions, there
was no bar in place to hold the boards in (or someone removed the bar from
this one, but I see no indications that this was so). So while the rest of
the flip chips were secured, I overlooked these in guiding the seller in
prepping it for shipping.
Two of the boards sustained pretty major damage, about a half a dozen of
the little "gum drop" looking transformers (DEC refers to them as T-2052)
broke off and most of them fell out and will never be found again.
I realize it's a long shot, but does anyone have:
- Any spare G603s (working or no, as long as the transformers are there)
- Any spare T-2052s (or know of a source)
- Any idea what the T-2052 *was* so I can try to replace them. I haven't
found much detail as of yet.
(The G603 schematic is here:
http://svn.so-much-stuff.com/svn/trunk/Eagle/projects/DEC/Gxxx/G603/G603E.p…
)
Thanks, all!
- Josh
13 Apr
13 Apr
3:36 p.m.
I realize it's a long shot, but does anyone have:
- Any spare T-2052s (or know of a source)
- Any idea what the T-2052 *was* so I can try to replace them. I haven't
found much detail as of yet.
Good news on this front!
I had previously obtained a data sheet for the T2037, a similar transformer.
I extracted 4 each T2037 and T2052 from a broken G228, and today I was
able to get measurements off of them:
T2037:
A: 230uH, 170 mohm primary, 42.9uH 100 mohm secondary
B: 220/170, 41.6/100
C: 232/170, 43.8/60
D: 231/170, 43/80
These are consistent with 16 turns and 7 turns of #33 wire, wound on
an FT37-77 toroid per the instructions on the data sheet, and also with
the 220 uH /43 uH 20% specs that appear there.
Here are the T2052 measurements:
A: 597/320, 597/320
B: 530/270, 530/270
C: 34/1040, 24/680
D: 551/280, 551/280
Ignoring "C", which is quite likely broken in some way, these are
consistent with a 25 turn 1:1 transformer. I'm not sure what they
are wound with, as #33 wire should give a lower DC resistance.
(#34 is closer. It's also possible that they changed cores, but I
suspect that they are also wound on FT37-77 cores.)
It's possible that a fairly standard modern 1:1 pulse transformer
could be substituted. The 78615/2JC, for instance is 500uH, 1:1
if you ignore the center tap pins.
Vince
4:01 p.m.
Using a t-2052 build up a test fixture, a pulse generator and? a
oscilloscope and if have access to one a high bandwidth current probe. Use
the 2052s you have, record the curves etc and then make up some test
transformers.
-Pete component engineer in a former life.
On Apr 13, 2017 3:36 PM, "Vincent Slyngstad via cctalk" <
cctalk at classiccmp.org> wrote:
I realize it's a long shot, but does anyone have:
- Any spare T-2052s (or know of a source)
> - Any idea what the T-2052 *was* so I can try to replace them. I haven't
> found much detail as of yet.
Good news on this front!
I had previously obtained a data sheet for the T2037, a similar
transformer.
I extracted 4 each T2037 and T2052 from a broken G228, and today I was
able to get measurements off of them:
T2037:
A: 230uH, 170 mohm primary, 42.9uH 100 mohm secondary
B: 220/170, 41.6/100
C: 232/170, 43.8/60
D: 231/170, 43/80
These are consistent with 16 turns and 7 turns of #33 wire, wound on an
FT37-77 toroid per the instructions on the data sheet, and also with the
220 uH /43 uH 20% specs that appear there.
Here are the T2052 measurements:
A: 597/320, 597/320
B: 530/270, 530/270
C: 34/1040, 24/680
D: 551/280, 551/280
Ignoring "C", which is quite likely broken in some way, these are
consistent with a 25 turn 1:1 transformer. I'm not sure what they are
wound with, as #33 wire should give a lower DC resistance.
(#34 is closer. It's also possible that they changed cores, but I suspect
that they are also wound on FT37-77 cores.)
It's possible that a fairly standard modern 1:1 pulse transformer could be
substituted. The 78615/2JC, for instance is 500uH, 1:1 if you ignore the
center tap pins.
Vince
15 Apr
15 Apr
6:15 p.m.
Do we know who made the transformers originally? I maintain some old
industrial hardware designs that used pulse transformers from the
mid-60's and I may still have catalogs and/or data sheets.
-chuck
On Thu, Apr 13, 2017 at 7:01 PM, Pete Lancashire via cctalk
<cctalk at classiccmp.org> wrote:
Using a t-2052 build up a test fixture, a pulse
generator and a
oscilloscope and if have access to one a high bandwidth current probe. Use
the 2052s you have, record the curves etc and then make up some test
transformers.
-Pete component engineer in a former life.
On Apr 13, 2017 3:36 PM, "Vincent Slyngstad via cctalk" <
cctalk at classiccmp.org> wrote:
> I realize it's a long shot, but does anyone have:
>>
>
> - Any spare T-2052s (or know of a source)
>> - Any idea what the T-2052 *was* so I can try to replace them. I haven't
>> found much detail as of yet.
>>
>
> Good news on this front!
>
> I had previously obtained a data sheet for the T2037, a similar
> transformer.
>
> I extracted 4 each T2037 and T2052 from a broken G228, and today I was
> able to get measurements off of them:
>
> T2037:
> A: 230uH, 170 mohm primary, 42.9uH 100 mohm secondary
> B: 220/170, 41.6/100
> C: 232/170, 43.8/60
> D: 231/170, 43/80
>
> These are consistent with 16 turns and 7 turns of #33 wire, wound on an
> FT37-77 toroid per the instructions on the data sheet, and also with the
> 220 uH /43 uH 20% specs that appear there.
>
> Here are the T2052 measurements:
> A: 597/320, 597/320
> B: 530/270, 530/270
> C: 34/1040, 24/680
> D: 551/280, 551/280
>
> Ignoring "C", which is quite likely broken in some way, these are
> consistent with a 25 turn 1:1 transformer. I'm not sure what they are
> wound with, as #33 wire should give a lower DC resistance.
> (#34 is closer. It's also possible that they changed cores, but I suspect
> that they are also wound on FT37-77 cores.)
>
> It's possible that a fairly standard modern 1:1 pulse transformer could be
> substituted. The 78615/2JC, for instance is 500uH, 1:1 if you ignore the
> center tap pins.
>
> Vince
>
9:04 p.m.
On 04/15/2017 08:15 PM, Charles Dickman via cctalk wrote:
Do we know who made the transformers originally? I
maintain some old
industrial hardware designs that used pulse transformers from the
mid-60's and I may still have catalogs and/or data sheets.
Some of the big names are Pulse Engineering and Rhombus
Industries. I think DEC used Pulse Engineering in a lot of
PDP-11 and VAX vintage stuff, so maybe they used them back
in the PDP-8 days, too.
Jon
16 Apr
16 Apr
12:06 a.m.
From: Charles Dickman via cctalk: Saturday, April 15, 2017 6:15 PM
Do we know who made the transformers originally? I
maintain some old
industrial hardware designs that used pulse transformers from the
mid-60's and I may still have catalogs and/or data sheets.
The DEC part number for these parts is 16-05794. Variant -05 is the
T2037, and variant -02 is the T2052.
I don't remember any more how I did it, but at some point, I tracked
these down to bhelectronics.com. The information they were able to
provide for the T2037 shows the logo of Buckbee Mears Co. of
St. Paul, Minn. and the stamp of the "Pulse Transformer Div".
Presumably BH Electronics acquired Buckbee Mears at some point.
They also indicate that they were manufactured to DEC's spec's.
I wouldn't expect them to have much more information -- they
indicated they'd sent me what they had, and that was paper
records back in 2004. It would be great to turn up some old
data sheets, though. The "code ident no." on the manufacturing
docs is 08450, and the number 500-0587 is also repeated on
every page.
Vince
2807
days inactive
2816
days old
5 comments
5 participants
participants (5)
-
chd＠chdickman.com -
derschjo＠gmail.com -
elson＠pico-systems.com -
pete＠petelancashire.com -
v.slyngstad＠frontier.com