Topward TPS-4000D PSU Manual ?

[David_AVD]

I have a Topward TPS-4000D power supply that I'd like to find the manual (schematics and adjustments) for.  It's the version with a single digital display that's switchable between voltage and current for each of the main outputs.

A Google search only found the analogue metering version and the basic control boards look similar, but it would be nice to get the right one.

[David_AVD]

Here's a picture of the power supply as I received it and then all cleaned up.

The fuse holder was broken when I got it and the two main filter caps had small cracks in the rubber, but that's the only parts that needed replacing.

I paid less than $100 all up for the unit (eBay) and parts, so I'm happy to have a dual tracking 0..30V @ 3A and 5V @ 3A power supply for that.

[lowimpedance]

Nice tidy unit, I would be very happy too.
 At work there are quite a large number of the older moving coil metered dual supplies from Topward. (TPS4000, no suffix). All quite old but still going strong. The only problems were some dried out electrolytics and oddly enough a poor mains earth connection on all the units that was discovered after electrical safety testing with more recent types of appliance testers.
Clearly a manufacturing  issue!. All units have been modded to comply with the electrical standards and are back in service again for many years to come.
 enjoy
 LowZ

[David_AVD]

I ran the PAT unit over this unit before I powered it up just to be sure.   

[floobydust]

I know-  stale thread but I found Topward 4000 family service manual here, or PM me.
I refurbed a few Topward TPS-4000 family bench PSU's, because solid aluminium front panel and low-noise analog design and keeping old stuff out of landfill.

The master regulation circuitry, op-amps etc. are all referenced to the power supplies (+) output.
So what you'd expect to be ground- is actually floating tied to (+) output. Once you get that, troubleshooting is easier.

The pass driver transistor usually cooks and dies. I added 25R 1W resistor to limit its collector current.

There are protection diodes missing on these designs, from (+ or -) output to main filter cap. Basically, across the pass-transistor C-E. Stops them from blowing up if you connect batteries to the output when off or dialed to zero. Added two 1N5404's.

[aargee]

I know-  stale thread but I found Topward 4000 family service manual here, or PM me.
I refurbed a few Topward TPS-4000 family bench PSU's, because solid aluminium front panel and low-noise analog design and keeping old stuff out of landfill.

The master regulation circuitry, op-amps etc. are all referenced to the power supplies (+) output.
So what you'd expect to be ground- is actually floating tied to (+) output. Once you get that, troubleshooting is easier.

The pass driver transistor usually cooks and dies. I added 25R 1W resistor to limit its collector current.

There are protection diodes missing on these designs, from (+ or -) output to main filter cap. Basically, across the pass-transistor C-E. Stops them from blowing up if you connect batteries to the output when off or dialed to zero. Added two 1N5404's.

Thanks floobydust, I have two Topward 4000s here (one 30V and one 60V) and they've been on my mind to 'de-dust' them for a while now.
I see a few re-furbs coming up, they are still in weekly use.
I remember as a young tech in the '80s installing the RP diodes in the very 30V unit I diverted from the dumpster.
 

[floobydust]

Rigol 832 triple output bench power supply, lovely OLED and keypad, surely better than the "old" trusty linear PSU's I'd been using.

Younger engineers kept blowing things up with the Rigol- and when I investigated, the current-limiting is super slow and massive overshoot. It's not good with dynamic loads at all.

LM741 kicks ass compared to DAC/ADC MCU trying to correct ooops too late.

[David_AVD]

LM741 kicks ass compared to DAC/ADC MCU trying to correct ooops too late.

I don't think that any of the "digital" power supplies have the DAC or ADC in the control loop.  The DAC sets the desired voltage and the ADC simply reads it for the display.

[floobydust]

There's two DACs- voltage and current-limit. Whether it is firmware or an op-amp loop, the Rigol 832 is just too slow when entering CC mode it takes forever to back off and damages your load.

[David_AVD]

That may be, but it's nothing to do with the digital control AFAIK.