POWER DESIGNS PRECISION POWER SUPPLIES

[CatalinaWOW]

Not digital - I worship at the church of HP611x.

If it makes you feel better I have three other PD supplies that I am quite happy with.  Just think that PD got trapped in the technology limits and the attempt to be clever on the 2005A.  It works great, but is no fun to use.  Of course if you are not changing voltages frequently, particularly if you are not going back and forth over the decade boundary it is just fine.

[rsjsouza]

T has better regulation than S. I'm shopping for my son's home lab (3rd year EE) and thought a little old school PSU would fit the bill. 50V @ 1.5A should be plenty. No way he is touching my 2020B... no way. 

BTW, is there a Wiki on EEVblog? Seems to be almost no resources out there for PD collectors... which I guess I am now! 

I have a 5015A and its performance is absolutely amazing - I tested it throughout its range and the ripple was quite low and the voltage was quite stable. The only letdown for me is that it does not work as a current source.

[don.r]

T has better regulation than S. I'm shopping for my son's home lab (3rd year EE) and thought a little old school PSU would fit the bill. 50V @ 1.5A should be plenty. No way he is touching my 2020B... no way. 

BTW, is there a Wiki on EEVblog? Seems to be almost no resources out there for PD collectors... which I guess I am now! 

I have a 5015A and its performance is absolutely amazing - I tested it throughout its range and the ripple was quite low and the voltage was quite stable. The only letdown for me is that it does not work as a current source.

Is the current delivery not flat up to 50V?

[mtdoc]

Not digital - I worship at the church of HP622x.

That's ok.  I'm bi-denominational.  Currently with 4 PD supplies and 7 HP supplies including a 6114, 6115, 6632a and 6632b.  Shit - when I list them like that it makes me realize I have a PSU issue...

[bitseeker]

Inside, for sure, but I usually don't stare at the internals unless there is an issue or after initial purchase for curiosity sake. When my 5335A Counter died, I parted it out and still have a stack of aluminum left (PM me for parts!). HP is all about the specs and durability which is all well and good but not so much visual appeal, especially for a collector. At any rate, finding a decent HP supply for under $50 is tough but PDs do drop under this price frequently.

Yep, agreed. Unfortunately, most PD supplies don't support CC operation, just a crowbar. IIRC the only ones I've seen with CC are the precision ones and the newer digital display ones. Nevertheless, I've got a fair collection of them.

I know this thread was about the Precision designs but I posted here because it appears to be the only PD thread in the forum with traction.

It's OK. It's been wandering in and out of the precision models for a while.

[bitseeker]

I have a 5015A and its performance is absolutely amazing - I tested it throughout its range and the ripple was quite low and the voltage was quite stable. The only letdown for me is that it does not work as a current source.

Yeah, most don't. The precision models (e.g., 2005, 2005A, 2010, 2020B, 5020) and the newer models with 7-segment displays (e.g., 6050C, TW347D, TW5005D) do.

[bitseeker]

That's ok.  I'm bi-denominational.  Currently with 4 PD supplies and 7 HP supplies including a 6114, 6115, 6632a and 6632b.  Shit - when I list them like that it makes me realize I have a PSU issue...

It's OK, mtdoc. GAS comes in many forms. Mine started with power supplies.

[rsjsouza]

T has better regulation than S. I'm shopping for my son's home lab (3rd year EE) and thought a little old school PSU would fit the bill. 50V @ 1.5A should be plenty. No way he is touching my 2020B... no way. 

BTW, is there a Wiki on EEVblog? Seems to be almost no resources out there for PD collectors... which I guess I am now! 

I have a 5015A and its performance is absolutely amazing - I tested it throughout its range and the ripple was quite low and the voltage was quite stable. The only letdown for me is that it does not work as a current source.

Is the current delivery not flat up to 50V?

Oh, no. I meant that the current control is a clamp. In other words, the output drops to zero if the limit is reached, requiring power cycling the power supply.

[don.r]

T has better regulation than S. I'm shopping for my son's home lab (3rd year EE) and thought a little old school PSU would fit the bill. 50V @ 1.5A should be plenty. No way he is touching my 2020B... no way. 

BTW, is there a Wiki on EEVblog? Seems to be almost no resources out there for PD collectors... which I guess I am now! 

I have a 5015A and its performance is absolutely amazing - I tested it throughout its range and the ripple was quite low and the voltage was quite stable. The only letdown for me is that it does not work as a current source.

Is the current delivery not flat up to 50V?

Oh, no. I meant that the current control is a clamp. In other words, the output drops to zero if the limit is reached, requiring power cycling the power supply.

Something must have changed between the A and the S because mine limits like a charm. Once the limit is reached the voltage starts dropping keeping current constant. Raise the limit and the voltage rises again. The only downside is that you need to set the limit with a dead short across the terminals.

[nanofrog]

T has better regulation than S. I'm shopping for my son's home lab (3rd year EE) and thought a little old school PSU would fit the bill. 50V @ 1.5A should be plenty. No way he is touching my 2020B... no way. 

BTW, is there a Wiki on EEVblog? Seems to be almost no resources out there for PD collectors... which I guess I am now! 

I have a 5015A and its performance is absolutely amazing - I tested it throughout its range and the ripple was quite low and the voltage was quite stable. The only letdown for me is that it does not work as a current source.

Is the current delivery not flat up to 50V?

Oh, no. I meant that the current control is a clamp. In other words, the output drops to zero if the limit is reached, requiring power cycling the power supply.

Something must have changed between the A and the S because mine limits like a charm. Once the limit is reached the voltage starts dropping keeping current constant. Raise the limit and the voltage rises again. The only downside is that you need to set the limit with a dead short across the terminals.

FWIW, the images I see of the 5015A have a current knob (proper CC) rather than a set screw for current as is the case on other models (some with letters, some without).




My TP343B is one that uses set screws for both current and over voltage (clamp & crowbar respectively). So if either OV or current trip, it has to be power cycled to reset it. Not a big deal, but I did pick up a GW Instek GPC-3020 for instances where I do need a proper CC capable PSU as I couldn't pass it up at just under $60 shipped (triple output, 2x @ 0 - 30V & 0 - 2A, and 1x fixed output @ 5V & 3A). BTW, they're still available on eBay (here).

[Barbouri]

Just finished working on two Power Designs power supplied that I purchased on Ebay.
The first one is a 6050D that was in fairly poor cosmetic shape, and missing some components.
It took quite a bit of work, but I am quite happy with the final results.


The second unit is a 6150 that mainly needed mechanical repairs and some cleaning.
I haven't seen many examples of this power supply, and still need some information for which potentiometers are used for calibrating the current meter.


I documented the work on both power supplies with lots if hi-res photos on my blog pages.
https://www.barbouri.com/2017/11/29/power-designs-6050d-power-supply-repair/ 6050D
https://www.barbouri.com/2017/11/30/power-designs-6150-universal-dc-power-source-restoration/ 6150

Barbouri

[bitseeker]

Welcome to the forum, Barbouri. Nice job on the 6050D. It looks great. I'll check out your blog for the details. I have a couple of 6050A, so I'm curious to see what the D is like inside.

Yeah, I see 6150 around on occasion, but they are rather rare. I've never worked on one.

[Barbouri]

Hi bitseeker,
Even though the 6050D in a more recent variant of the 6050 series, I was impressed with the quality of construction and engineering.
My only disappointment was the use of zip-ties for cable management, instead of waxed lacing cord.
I acquired a basket-case Power Designs 6050C on Ebay today. Should be interesting...

Thanks for the welcome,
Barbouri

[bitseeker]

It's also interesting that the PCB on the 6050D, despite being much newer, looks like the same vintage as the 6050A.

Where did you get the replacement knobs for the 6050D? Those look pretty good. I'd still like to find three originals for my TP340A.

Looking forward to your 6050C repair.

[rsjsouza]

Pretty nice work, Barbouri! Thank you for sharing.

I need to do some minimal TLC to my PD5015A as the ammeter is not working - everything else is in pristine condition and the noise/load is remarkable for a +/- 50 years old PS (mine has a General Dynamics calibration seal dated from 1969).

[Barbouri]

The knobs on the 6050D are from Digi-Key part #226-3148-ND and are  by Kilo International part#OESA-50-3-5

They do not sit as flush as the originals, but this unit came with only one knob. They are also not as tall as the originals, but in my opinion are a good match.

Unfortunately the recent 6050C has some shiny non-PD knobs on it, so will likely be getting the OESA-50-3-5 knobs for it too.

[rsjsouza]

I finally found the 5015A schematics.

[bitseeker]

Wow, nice find. Is that an original?

[rsjsouza]

Yes, it certainly is. Quite remarkable the design is dated from 1961! 

FWIW, the images I see of the 5015A have a current knob (proper CC) rather than a set screw for current as is the case on other models (some with letters, some without).

The diagram I got had some usage instructions about the CC control of the 5015A, and they indicate it is a crowbar method, not CC. It also says there the price was $234.50 FOB factory in 1961 ($1919.81 in today's money), while the specified ripple is rated at less than 0.001% with a maximum of 500 microvolts 

That is engineering, my friends. Especially considering they used "silicon transistor amplifiers for maximum reliability" and "pre-aged germanium power transistors with controlled parameters to insure interchangeability and field reliability" while guaranteeing that "automatic Ico compensation circuit eliminates the possibility of turn-on and turn-off transients" and "fifty hour pre-aging of power supplies prior to test"

As someone else hinted in a past discussion, I am suspicious they were in fact from another planet and graced us with their designs...

[bitseeker]

Yeah, the noise on these supplies is outstanding.

It seems most of the PD supplies have current crowbars. I've only seen CC mode in the precision versions and the ones with digital displays.

[ez24]

As someone else hinted in a past discussion, I am suspicious they were in fact from another planet and graced us with their designs...

Glad someone else believes this, since there is no internet history on them.  If something exists then it will be on the internet.  Since "they" do not exist but their products exist, something must be going on.  A logical explanation is aliens made them for some purpose that we do not know about.  Like help develop something for space flight that will take us to another planet.  Once this theory is proven then the value of these supplies will greatly increase.  I just hope humans will not become a food source like I think about every time I look at my power supply.  God forbid, the PD is not the alien (but just in case I use kind words when I talk to my power supply)

[bitseeker]

Well, one of my PD 6050A was owned by Grumman Aircraft.

[texaspyro]

Well, one of my PD 6050A was owned by Grumman Aircraft.

Meh,  mine were owned by Beldar Conehead from Remulac.  I traded him mass quantities of beer for them.   

[bitseeker]

Show off!

[Barbouri]

Repairs are progressing on the Power Designs 6050C.


PO did replace the leaking 22,000 uF 16V capacitor, but didn't bother to clean up the electrolyte that dripped down to the circuit board below.


Circuit board bottom after cleaning, repair, and replacing capacitors.
It is currently functional, but I need to do a full re-cap, and a few mechanical repairs before it is finished.

Also added to the bench is a Power Designs 2005A won on auction from Ebay for $26.00 plus shipping.
After an afternoon of cleaning and minor repairs. I still need to find a pair of rear feet for this unit.
I ended up using polarizing film instead of white paint for repairing the digital dial window.




Greg (Barbouri)