Author Topic: GW Instek PSP-603 60V 3.5A power supply (short) review and teardown  (Read 9805 times)

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Offline c_04

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Re: GW Instek PSP-603 60V 3.5A power supply (short) review and teardown
« Reply #25 on: April 14, 2018, 09:08:26 pm »
I unsoldered 24c02B and still nothing. Without this memory i hear only 2 beeps and thats it. Erased and soldered back. I tryided to copy content but i made mistake and i lost it. Now i will check maybe something with oscilloscope. Not much to do with 10MHz tool. But maybe...
I will try to burn another 27C512 with my copy but i dont belive it can help.
Maybe someone of you have working one bin or hex?
Cheers
G
 

Online wraper

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Re: GW Instek PSP-603 60V 3.5A power supply (short) review and teardown
« Reply #26 on: April 14, 2018, 10:04:10 pm »
Erased and soldered back. I tryided to copy content but i made mistake and i lost it.
At least for this older PSU version there is calibration manual available.
 
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Offline c_04

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Re: GW Instek PSP-603 60V 3.5A power supply (short) review and teardown
« Reply #27 on: April 14, 2018, 10:42:05 pm »
Thank you very much. :)
I didnt moved any pots - should stay calibrated.
Checked with oscilloscope. Theres something. SCL and SDA - at least higher level than 0V when turning on. Not see peaks or something like that but maybe because of my oscilloscope. Also xtal looks present but in similar way.
 

Offline nctnicoTopic starter

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Re: GW Instek PSP-603 60V 3.5A power supply (short) review and teardown
« Reply #28 on: April 14, 2018, 10:44:31 pm »
Are the SCL and SDA lines at 5V after the PSU has started?
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 
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Offline c_04

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Re: GW Instek PSP-603 60V 3.5A power supply (short) review and teardown
« Reply #29 on: April 14, 2018, 10:46:02 pm »
Im not sure its showing me correctly but its rather 2V. Will check again with multimeter maybe too.
 

Offline c_04

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Re: GW Instek PSP-603 60V 3.5A power supply (short) review and teardown
« Reply #30 on: April 14, 2018, 10:48:15 pm »
With multimeter both shows 5V. But constant i think.

Hmm at different pins of U1 i see some activity. I thought that this uC is dead. Now looks opposite. 7832 it sends only some noises. I have somewhere 8031 but has only half of ram 8032 - i cant check it that way.
« Last Edit: April 14, 2018, 10:57:30 pm by c_04 »
 

Online wraper

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Re: GW Instek PSP-603 60V 3.5A power supply (short) review and teardown
« Reply #31 on: April 14, 2018, 11:14:53 pm »
Thank you very much. :)
I didnt moved any pots - should stay calibrated.
Checked with oscilloscope. Theres something. SCL and SDA - at least higher level than 0V when turning on. Not see peaks or something like that but maybe because of my oscilloscope. Also xtal looks present but in similar way.
It's a mix of digital calibration + pots.
 
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Offline c_04

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Re: GW Instek PSP-603 60V 3.5A power supply (short) review and teardown
« Reply #32 on: April 14, 2018, 11:28:52 pm »
Ive bought 5pcs of P80c32 for other projects and i will try to check if that will work in this power supply. I will check once more 27c512 - yesterday i was able to read it but im not sure about today. Ive checked closer whats happening to and from 27c512. Looks that both processors are sending and receiving something. When i short SW1 then starts some activity on SCL and SDA. Normallny is flat line there. After turning on is there send high and goes back to flat line. Shorting SW1 only 2 times produce similar effect after that when i try to short again nothing happening. Checked 74hc373 and looks fine. No idea what else i can check.
There must be something working because ive seen twice fan was started and after some time stoped.
Cheers
G
« Last Edit: April 15, 2018, 01:07:12 am by c_04 »
 

Offline c_04

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Re: GW Instek PSP-603 60V 3.5A power supply (short) review and teardown
« Reply #33 on: April 19, 2018, 11:58:03 am »
Hello Guys
My way of thinking was good but not that chip was damaged as i thought. Today ive got 80C32 and i replaced old one 78c032c from Winbodond. After short boot my power supply wake up after probably 10 years lying on some storage.
So real thanks for each oneof you who forced me to make some measurements. Without you probably i would be sure that this power supply is unfixable.
Thanks very much again and...
Cheers
Greg
 

Offline nctnicoTopic starter

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Re: GW Instek PSP-603 60V 3.5A power supply (short) review and teardown
« Reply #34 on: April 19, 2018, 12:16:39 pm »
Thanks for feedback about the actual problem! These power supplies are quite nice.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline c_04

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Re: GW Instek PSP-603 60V 3.5A power supply (short) review and teardown
« Reply #35 on: April 19, 2018, 12:30:30 pm »
But unfortunately customer service is crap. Manufacturer doesnt reply for any questions.
No one wants to service these power supplies. Farnell said that if its still under warranty they can help. Similar TME in Poland - they said that they can fix it only if it was purchased in their store. I asked many other services that spacialise with measurement gear. All of them said that they are not able to fix this power supply. At last when i was pissed enough i started to dig there. In fact is not much inside. And if any uC is good should start just by the kick. Anyway i start to think - what can be reason if LCD doesnt work and any entered values do not makes response. As i thought was uC... next you know :)
Cheers
G
 

Offline c_04

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Re: GW Instek PSP-603 60V 3.5A power supply (short) review and teardown
« Reply #36 on: April 21, 2018, 12:55:30 am »
Hi
Ive observed another issue. Power supply is occasionally reseting. I checked some capacitors C25 (i think), C29, C33, C37, C49, C36 - replaced this one with Sanyo. This power supply probably was previously serviced because all caps are like new. What else could be the reason of resetting? Once even i wasnt able to set any value because constant resetting but then i pressed wire connectors and everything back to occasional reseting.
Maybe its somehow connected with that i replaced 78C032 to 80C32?
I will replace eprom maybe... but no idea it can help.
Cheers
G

P.S. Interresting... when ive replaced eprom with 27C512 (UV erasable) power supply is reseting even when i try to sen any value. That means there something is too slow. Maybe I need 80C32 little faster. Maybe thats the reason.
« Last Edit: April 21, 2018, 01:02:04 am by c_04 »
 

Offline c_04

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Re: GW Instek PSP-603 60V 3.5A power supply (short) review and teardown
« Reply #37 on: April 21, 2018, 03:52:14 am »
I must say that there is definitely something wrong with contact between uC and socket. I replaced uC with another one and everything is back to normal. Checked another eproms (UV) and every of them works fine no resetings. I replaced back again the same uC which was before this test and works as a charm.
Of course this dead 78c032 is still dead ;)
So thats another point - bad contacts and weak quality sockets.
Cheers
G
« Last Edit: April 21, 2018, 03:55:10 am by c_04 »
 

Offline byhazin1453

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Re: GW Instek PSP-603 60V 3.5A power supply (short) review and teardown
« Reply #38 on: December 07, 2020, 08:05:05 pm »
HELLO, I would be glad if you can help me know the reason for this problem on my device.
« Last Edit: December 07, 2020, 09:09:45 pm by byhazin1453 »
 


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