DIY Frame for SG5010 etc ???


David Slipper
 

Is it practical to build a DIY mainframe (like the TM5006) to house and use the likes of a SG5010/DC5010/FG5010 ???

I have been offered these at a reasonable price but without the mainframe which seem expensive.

Regards,
Dave


Ke-Fong Lin
 

TM5003 and TM5006 can be found quite cheap. Look on ebay, there should be less than $200.
Also, the SG5010 can be modified (need to unscrew and "retract" the GPIB related connector board) the to be used on the older TM503/TM504/TM506 mainframes.

It's possible to run without a mainframe, I've done it for debugging purpose : https://groups.io/g/TekScopes/photo/243643/2878191?p=created%2C%2Cextender%2C20%2C2%2C100%2C0
The mainframes are supplying multiple voltages (DC and AC), I don't think it would be much cheaper to do a DIY mainframe, when originals can be found rather cheap.


Jared Cabot
 

It could be done with a bit of metal work and a couple transformers if you can find them cheaply enough, but in this case DIY may end up more expensive in the end if buying all new parts.

I have designed replacement PCB's for a TM503 mainframe that can get you staeted at least.

https://www.youtube.com/watch?v=VkNRUI_QtWo


 

here is the TM500-series plug-in interface page on the TekWiki, which will tell you what voltages are needed https://w140.com/tekwiki/wiki/TM500_Series_plug-in_interface

The power modules also provide NPN and PNP series pass transistors that can be (and are) used by plug-ins, so it's just a dumb power bus. Depending on what plug-ins you want to test those pass transistors may be vital.

Finally, there is some important relationship between the different 25 VAC rails that I don't fully understand. They need to have a specific phase with respect to each other (and maybe to the 17.5 VAC rail?) or Bad Things[TM] can/will happen.

-- Jeff Dutky


Harvey White
 

The AC windings are often put in series.  Getting one out of phase results in far less voltage than you'd want.  The average TM500 mainframe checker should have tests available to make sure that the phases are correct (so they add).

History says that some TM500 mainframes were wired improperly. It made a difference on some plugins where the AC phases were added together to make an on-module power supply.  PG505 is one, and I suspect that the voltmeters were much the same.

There's a way that you can use opto-isolators to check phasing when using a microprocessor.  Another way with the same microprocessor would be to measure peak voltages vs. time to determine phasing.

Harvey

On 10/6/2021 7:49 PM, Jeff Dutky wrote:
here is the TM500-series plug-in interface page on the TekWiki, which will tell you what voltages are needed https://w140.com/tekwiki/wiki/TM500_Series_plug-in_interfaceT

The power modules also provide NPN and PNP series pass transistors that can be (and are) used by plug-ins, so it's just a dumb power bus. Depending on what plug-ins you want to test those pass transistors may be vital.

Finally, there is some important relationship between the different 25 VAC rails that I don't fully understand. They need to have a specific phase with respect to each other (and maybe to the 17.5 VAC rail?) or Bad Things[TM] can/will happen.

-- Jeff Dutky





Vintage Test
 

David,

I have all of the electronics, and most of the mechanics of a TM5006 available - it’s missing only it’s mains transformer. I couldn’t find one to repair it, so and waited for another TM5006 to come up at the right price ! Where are you?

Cheers,
Mel

--
you can never have enough oscilloscopes, DMMs, valve testers or soldering irons . . .


David Slipper
 

I'm in the uk.

Get BlueMail for Android<https://bluemail.me>

On 7 Oct 2021, at 08:17, "Vintage Test via groups.io<http://groups.io>" <icloud.com<mailto:mel.purcell=<a>@groups.io target=_blank>mel.purcell=icloud.com<http://icloud.com>@groups.io> wrote:

David,

I have all of the electronics, and most of the mechanics of a TM5006 available - it’s missing only it’s mains transformer. I couldn’t find one to repair it, so and waited for another TM5006 to come up at the right price ! Where are you?

Cheers,
Mel


Vintage Test
 

Me too - Scotland, just outside Glasgow. Do you want any of this stuff - I can PM you with some pics if you like?

Cheers,
Mel

--
you can never have enough oscilloscopes, DMMs, valve testers or soldering irons . . .


David Slipper
 

I may have tracked one down :-)

Thanks anyway.
Dave

On 07/10/2021 12:07, Vintage Test via groups.io wrote:
Me too - Scotland, just outside Glasgow. Do you want any of this stuff - I can PM you with some pics if you like?

Cheers,
Mel


Vintage Test
 

Ok David,

Let me know if you still need any bits. In the meantime, if anyone else would like any parts of a TM5006 - there’s virtually a whole unit, apart from the mains transformer and a few pieces of trim and the guide rails. PM me if you want any of it - the unit was totally functional and was used daily before the tx melted!

Cheers,
Mel

--
you can never have enough oscilloscopes, DMMs, valve testers or soldering irons . . .


SCMenasian
 

If you check the schematics for the some TM50x mainframes, you will see a dot a one end of each 25 VAC and the 17.5 VAC transformer winding. These dots mark the polarity for phasing and a sufficiently sensitive ohmmeter should allow you to trace the dotted ends to the interface connector; however, you probably don't have to do this. The dotted ends all go to the 'A' side of the interface connectors. Note that not all schematics show the dots (My TM6506 does; the TM504 doesn't).

Stephen


EJP
 

On Thu, Oct 7, 2021 at 12:05 PM, Harvey White wrote:

History says that some TM500 mainframes were wired improperly. It made a
difference on some plugins where the AC phases were added together to make an
on-module power supply.  PG505 is one, and I suspect that the voltmeters were
much the same.
The DM502, DM502A, and FG504 are definitely such.