Comments on: GQ-A305D Bench Power Supply Repaired

By: Owais Akhter

Owais Akhter — Sun, 14 Jun 2020 15:48:32 +0000

In reply to Memo.

I have the same power supply which has 4 to 5 milliamps out in display when I switch into milliamps mode. But quite accurate in Ampare mode. Could you please mention which variable I should adjust to reach at nearest value on display?I have checked milliamps value connected with my Fluke 87-V and it's showing 12mA but power supply display shows 8mA only in mA mode switch.

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By: elec lam

elec lam — Sun, 19 Nov 2017 16:43:35 +0000

i have 1 GQ-A305D power supply, when i put 4 variable back to position 0, but the clock still shows 6v, can you tell me how to fix it?

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By: Mick

Mick — Wed, 23 Aug 2017 11:25:58 +0000

Hi Robert, it is now August 2017 and I just ordered one of these power supplies. Hopefully the quality has improved by now. If not, I will use your article as reference to make repairs / improvement. Many Thanks.

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By: Robert Calk

Robert Calk — Tue, 10 May 2016 17:00:24 +0000

In reply to Jimmy.

Sorry Jimmy, but I gave my word. I'm not perfect by a long shot, but I do try my best to keep my word. Besides, these older style PCB's are not too difficult to study compared to multi-layered PCB's.

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By: Jimmy

Jimmy — Mon, 09 May 2016 13:32:04 +0000

Hi Robert. Its been long enough now. Do all us hobbyists a favour and leak that schematic that you promised to keep to yourself. There is nothing around and it will be greatly appreciated by many. No doubt you have perused countless schematics on the net..where do you think they came from? They were leaked by people just like yourself in similar circumstances. Its your turn now Robert. Thanking you on behalf of hobbyists world wide.

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By: fuba

fuba — Tue, 11 Aug 2015 17:26:05 +0000

great job!
but i think you spent more than 20$ for repairing!

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By: Raju varghese

Raju varghese — Sun, 24 May 2015 18:50:21 +0000

Hi Robert,
This is an Excellent work & good efforts please keep do sharing.

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By: Robert Calk

Robert Calk — Fri, 20 Feb 2015 13:57:40 +0000

In reply to Daud.

Thanks Daud.

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By: Daud

Daud — Thu, 19 Feb 2015 10:23:43 +0000

good efforts.

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By: Robert Calk

Robert Calk — Sun, 15 Feb 2015 23:54:30 +0000

In reply to Paris Azis.

Hi Paris,

I've decided to do the transistor & op-amps upgrades on my power supply. I checked on-line and they say that any 5 watt resistors below 1 Ohm will do for the emitters. I have some axial 5W 0.51 Ohm resistors that I will use.
I don't want to spend much more money on the unit than I need to, so I'm going to leave the heatsink in and see what kind of life I get out of the fan. It would probably be cheaper to just replace the fan if it will last a year or two running constant.
But I will add to the heatsink's mass when I find some good aluminum to add to it. But for now I'll just upgrade the power transistors & op-amps. Thanks for the help.
Robert

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