Author Topic: POWER DESIGNS PRECISION POWER SUPPLIES (Read 332740 times)

Barbouri · « **Reply #825 on:** May 13, 2018, 12:03:09 am »

A while back idpromnut designed a "drop-in" replacement display board for the Power Designs 6050C digital display.
https://www.eevblog.com/forum/projects/power-designs-6050c-display-mod/
He didn't publish his board design, so I thought I might make my own.

In researching possible LED 7 segment displays for the board, I came across some larger pin to pin compatible displays from Kingbright that were 0.4" character height vs the 0.3" of the originals.
For a few dollars each, I thought it was worth a try so I ordered 4 of them from Digi-Key.

They ended up working almost perfectly, but were considerably too bright with the existing current limiting resistors.
After swapping out the 47 and 200 ohm resistors with 330 and 1K ohm resistors respectively, I had a larger display on my PD 6050C without the cost of a new board.
This should work for both the PD 6050C & 6050B power supplies.

EDIT: I ended up increasing the current limiting resistors to 750 and 4.7K $\$\Omega\$$ as the display was still a bit too bright.
A side benefit of the lower intensity is that the display color has shifted more to a red than the orange-red before the change.

I documented the PD 6050C restoration and modification with lots of photos on my blog post https://www.barbouri.com/2018/05/12/power-designs-6050c-power-supply-display-upgrade/

bitseeker · « **Reply #826 on:** May 15, 2018, 03:14:16 am »

That looks great, Barbouri! A very nice upgrade, indeed. Is the 6050D display board different from B and C? I only have the A models.

Barbouri · « **Reply #827 on:** May 15, 2018, 04:13:09 am »

Quote from: bitseeker on May 15, 2018, 03:14:16 am

That looks great, Barbouri! A very nice upgrade, indeed. Is the 6050D display board different from B and C? I only have the A models.

Thanks bitseeker!

The PD 6050D is completely different from the B & C versions, and uses a single chip ICL7117 3½ digit monolithic
analog-to-digital converter.

bitseeker · « **Reply #828 on:** May 15, 2018, 04:26:45 am »

Ah, OK. Thanks for the info. Of those three digital variations, do you have a preference? If so, what makes it that much better than the others?

Barbouri · « **Reply #829 on:** May 16, 2018, 05:02:11 am »

Quote from: bitseeker on May 15, 2018, 04:26:45 am

Of those three digital variations, do you have a preference? If so, what makes it that much better than the others?

I would have to pick the PD 6050D as my preference. They are all great power supplies, and each of them has their own distinct features.
To me it seems that Power Designs, Inc. made an incremental improvement in each revision of the 6050 series that actually improved the usability.
What I like about the PD 6050D is the toggle switch selection of the meter volt / amps display, and the larger display. The front panel layout is also much cleaner and less cluttered.
Internally the control board is still similar to the earlier series, but many components have been upgraded to what at the time was the latest technology.

I may also be biased, as the PD 6050D was my first power supply from Power Designs, Inc.
It was well abused by the previous owner, and I spent several weeks restoring it to near original condition (minus the original knobs).
It is my daily go-to supply when I need a single voltage, and has taken over from my original HP 6200B supply.

https://www.barbouri.com/2017/11/29/power-designs-6050d-power-supply-repair/

bitseeker · « **Reply #830 on:** May 17, 2018, 01:22:25 am »

Heh, that V/A toggle switch on the D seems to have returned from the A series. From an aesthetics point of view, I still like the analog meter on the A, but the digital ones have constant current capability instead of just a crowbar.

The D seems to have even larger digits for its display. Also a nice improvement.

nanofrog · « **Reply #831 on:** May 17, 2018, 03:07:03 am »

FWIW, I'm fond of the analog meters on my TP343B.

No CC capability, so I use a GW Instek GPC-3020 for that. Oh, and the GPC-3020 also has analog meters.

rsjsouza · « **Reply #832 on:** May 18, 2018, 07:30:36 pm »

I couldn't resist sharing my 5015A (last cal in 1967!) at max current capacity (1.5A) supplying a state of the art 12-core 1.5GHz processor board. That is why these beasts took mankind to the moon!

Barbouri · « **Reply #833 on:** May 18, 2018, 08:05:50 pm »

Quote from: rsjsouza on May 18, 2018, 07:30:36 pm

I couldn't resist sharing my 5015A (last cal in 1967!) at max current capacity (1.5A) supplying a state of the art 12-core 1.5GHz processor board. That is why these beasts took mankind to the moon!

That is a nice looking PD 5015A.
Doing what it was designed to do, even after many decades.

bitseeker · « **Reply #834 on:** May 18, 2018, 11:16:09 pm »

Yeah, it seems a fair number of these are coming from government surplus, aviation, etc. One of mine is from Grumman Aircraft.

rsjsouza · « **Reply #835 on:** May 19, 2018, 01:57:25 am »

Certainly. Mine is from General Dynamics.

bitseeker · « **Reply #836 on:** May 19, 2018, 02:05:43 am »

Oh, is that what that sticker is? Cool!

rsjsouza · « **Reply #837 on:** May 19, 2018, 02:27:04 am »

The cal sticker is clearer. I just looked at my post below and realized I got the date wrong: the cal sticker is from 1969 not 1967.

https://www.eevblog.com/forum/testgear/photos-of-your-interesting-and-historical-test-equipment-stickers/msg778659/#msg778659

mtdoc · « **Reply #838 on:** July 02, 2018, 07:22:11 pm »

Currently on a trip to visit SWMBO’s mom in Michigan and her alma matter University of Michigan. UM has a property disposition warehouse where they dispose of lab equipment. I convnced wife and kids to make a detour for a visit. Mostly bio lab equipment with high end microscopes, centrifuges, HPLC equipment, the usual computer crap, etc. But I also found these on a shelf selling for $25 each. My GAS kicked in and I couldn’t resist (despite having way more PSUs than I need).

I decided to look around more first and not carry the heavy beast with me. Soon after, I see one being purchased at the checkout and rush back to get one of the 2 remaining. There was a guy looking at them a when he saw me grab one he grabbed the last one (though he later changed his mind).

It powers up and appears to put out correct voltages. Will load test it when I get home. It will be coming on the plane as a carry on.

rsjsouza · « **Reply #839 on:** July 02, 2018, 08:19:17 pm »

Wow, I would love to have one of these, especially for $25 with zero shipping. You are a lucky man.

mtdoc · « **Reply #840 on:** July 02, 2018, 10:00:33 pm »

Quote from: rsjsouza on July 02, 2018, 08:19:17 pm

Wow, I would love to have one of these, especially for $25 with zero shipping. You are a lucky man.

Thanks. Yeah, they are heavy beasts and shipping is a b**** which is why I never considered one before. But once I was looking at one close up, it was so beautiful, I‘m sure I would have happily paid 4x as much.

nanofrog · « **Reply #841 on:** July 02, 2018, 10:31:40 pm »

Two words... YOU SUCK!

Bassman59 · « **Reply #842 on:** July 02, 2018, 10:56:37 pm »

Quote from: Barbouri on May 16, 2018, 05:02:11 am

I would have to pick the PD 6050D as my preference. They are all great power supplies, and each of them has their own distinct features.
To me it seems that Power Designs, Inc. made an incremental improvement in each revision of the 6050 series that actually improved the usability.

I have a 6050D, too, got it at a surplus 20-some-odd years ago. I use it all the time.

bitseeker · « **Reply #843 on:** July 02, 2018, 11:36:49 pm »

Excellent score, mtdoc! GAS or not, it's hard to turn these down, especially when you see one in good condition in person. Even better, you got an early TP340A with metal knobs instead of plastic ones (like mine).

If you run into any issues when you get home, ping me if you need comparisons with a working one.

Barbouri · « **Reply #844 on:** July 03, 2018, 03:57:30 am »

Great find, Congratulations!

Barbouri · « **Reply #845 on:** July 07, 2018, 03:53:43 am »

Updated 4-digit display for Power Designs 6050C.

Blog project page for PD 6050C 4-digit display upgrade https://www.barbouri.com/2018/07/07/upgrading-a-power-designs-inc-6050c-with-a-4-digit-plus-mode-display/

bitseeker · « **Reply #846 on:** July 07, 2018, 06:46:21 pm »

Looks great, Barbouri.

idpromnut · « **Reply #847 on:** July 08, 2018, 03:56:43 am »

And yes, I have since found the correct replacement for the voltage knob (on the left)!

EDIT: Ha! I didn't go back far enough, thanks for the shout out! I'll leave your post with all the glory, damn fine improvement sir!!!

bitseeker · « **Reply #848 on:** July 09, 2018, 05:03:11 am »

Bigger knob, more potential.

mtdoc · « **Reply #849 on:** July 13, 2018, 03:38:31 am »

I load tested my recent TP340A acquisition and it did just fine. The only thing was an occasional slight flicker of the fault light on Source A.
Opening it up, I found that R137 was burnt to a crisp. An easy replacement and the fault light flicker disappeared.

In an effort to see what this 1K resistor was doing and why it might have been burnt, I turned to the schematic. The schematic found in the TP340A manual I've downloaded from KO4BBs manual archive is almost illegible. That site also has a slightly better quality scan of the TP340 manual which is somewhat legible. But alas - no R137 on that model. In any case, it appears to be part of the crowbar circuit. Inspection did not reveal any other obvious issues and none of the always suspect tantalums appear shorted, so hopefully it will remain problem free.

If anyone has a clearer version of the manual or schematic, it would be much appreciated.

It was impressively clean inside and aside from the one burnt resistor, appeared almost brand new. It's interesting seeing some of the component changes in bitseekers newer unit. Best I can tell from date codes is mine was manufactured in the mid 1980s.

I'm really quite impressed with this unit. There are not published specs on the noise and ripple, but on my testing it was in the neighborhood of 50 uV, similar to my PD 2005a, 2010 and my HP 6114 and 6115s.


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Author Topic: POWER DESIGNS PRECISION POWER SUPPLIES (Read 332740 times)

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