Used-to-work GP32 BLU will not turn on. What to do?

[elmimmo]

Undusted, figuratively speaking, my old GP32 BLU, which back in the day used to work just fine and still looks immaculate. When switching it on the LED will turn red, but nothing will come on the screen, with or without the memory card in its slot. The backlight works fine.

What could I try to diagnose what the issue is and resurrect it?

 

[___]

hmm. could be weak batteries or some other issues. but that's the easiest to troubleshoot. try some brand new AA alkaline batteries. Or did you use an AC adapter? By nothing on the screen you mean that it is turning white?

 

[___]

@elmimmo hey there, do you have any news? I'd like to help, but need an update on what you have tried so far. It could be a bunch of things but if I were you, I'd try it with an AC Adapter and also with different brands of alkaline batteries. It's a known issue, that the gp32 will not boot with certain batteries, eventhough they are exactly on spec.

 

[alxm]

If you try an AC adapter, make sure it's center-negative. Most random ones I see are center-positive so they're no good for the GP32.

 

[EvilDragon]

Seems something common, two of my three GP32 do that... havened opened them to check what it could be yet though.

 

[___]

Might be a dried up capacitor. But you probably know that already @EvilDragon
If you find the cuplrit, let us know. My gp32 is still working perfectly, but you never know.

 

[elmimmo]

Excuse me for the silence. Two updates:

1. I made a mistake in the title of the thread: the console will not turn on. It said off but has been corrected already I see.
2. I got ahold of a proper adaptor (checked both voltage and polarity). Tried with the adaptor and no batteries. No dice. LED will turn red and backlight works fine. But the screen looks the same with the switch on as it does with it off: nothing on it whatsoever, all white, no color in any pixel, no nothing.

 

[Neelix]

Had you previously tried it with an incorrect adapter? 'cause that's a quick way to fry something, especially if you get the polarity reversed.

-Neelix

 

[___]

then it might still be an issue with power, but maybe because of some wonky capacitors. you could open the device after powering it for a little while (take it off the AC before you open it obviously) and check for bits that have gotten warm to find the potential culprit. I guess someone with experience could try a repair, but I am not sure if anyone here still does gp32 hardware stuff. I'd say recap the whole unit, but that's not really a guaranteed fix and I think most components are smd parts if I remember correctly. So changing those caps will be a nightmare and could mess up so much more when fucking it up...

 

[Nintastic]

Buy another one glad to help

 

[Dave18]

I've got the same issue, gp32 (non back lit) was working fine when I put it away but now doesn't work. Power light comes on but no display. I've checked the voltages and they seem OK and clock signals are being generated so I think the issue is with the eeprom that controls the initial boot. I've removed it but I cannot find a datasheet to work out what to replace it with. The markings say a91sc but despite much googling I cannot find anything concrete. This website http://monitor.espec.ws/section21/topic80446.html suggests it is a 4k eeprom but I have no idea if the alternatives they mention would be suitable. Does anyone have any idea about the eeprom specs?

Thanks

Dave
[doublepost=1525283847,1525281826][/doublepost]Worked it out thanks to this doc - http://www.farnell.com/datasheets/35643.pdf
Page 9-1 shows the coding format for A91SC and then 10-1 give the ordering info.
I've ordered these https://www.ebay.co.uk/itm/332512612367
When they arrive I'll flash them with new bios and see what happens. I'll report back (they will take about a month to arrive)

Dave

 

[EvilDragon]

I've got the same issue, gp32 (non back lit) was working fine when I put it away but now doesn't work. Power light comes on but no display. I've checked the voltages and they seem OK and clock signals are being generated so I think the issue is with the eeprom that controls the initial boot. I've removed it but I cannot find a datasheet to work out what to replace it with. The markings say a91sc but despite much googling I cannot find anything concrete. This website http://monitor.espec.ws/section21/topic80446.html suggests it is a 4k eeprom but I have no idea if the alternatives they mention would be suitable. Does anyone have any idea about the eeprom specs?

Thanks

Dave
[doublepost=1525283847,1525281826][/doublepost]Worked it out thanks to this doc - http://www.farnell.com/datasheets/35643.pdf
Page 9-1 shows the coding format for A91SC and then 10-1 give the ordering info.
I've ordered these https://www.ebay.co.uk/itm/332512612367
When they arrive I'll flash them with new bios and see what happens. I'll report back (they will take about a month to arrive)

Dave

Same with mine. Seems like a common issue with these little buggers. Hopefully you'll have some success.

Sent from my XT1650-03 using Tapatalk

 

[Dave18]

Chinese seller cancelled order so ended up getting some compatible replacements locally. Bad news is it didn't fix the problem.

Further investigation shows that while the S3C2400X01 is receiving both the 12mhz and 32khz clocks it isn't outputting an sclk (for the sram) or a vclk for the video controller. I'm assuming the cpu is broken, surprising that a part like that would fail over time in storage though. I guess it might be a capacitor on the timing circuit but I'm beyond my knowledge now.

Unless anyone has any ideas I think it is the end for my Gp32.

Dave

 

[Arda]

Chinese seller cancelled order so ended up getting some compatible replacements locally. Bad news is it didn't fix the problem.

Further investigation shows that while the S3C2400X01 is receiving both the 12mhz and 32khz clocks it isn't outputting an sclk (for the sram) or a vclk for the video controller. I'm assuming the cpu is broken, surprising that a part like that would fail over time in storage though. I guess it might be a capacitor on the timing circuit but I'm beyond my knowledge now.

Unless anyone has any ideas I think it is the end for my Gp32.

Dave

can you (or somebody else) try and replace the cpu and see if it works? Too many dead units in the wild with the same symptoms.

https://www.alibaba.com/product-det...mponents-S3C2400X01-EER0-new_60467968056.html
cpu is available and around 20$ for a piece.

 

[levi]

I doubt the CPU is socketed on the GP32. I can't tell for sure from that image whether those CPUs for sale are in PLCC or QFP packages, but if they're not socketed they'll be high density surface mount QFP, and those are a pain to solder, with a high failure rate.

 

[drock]

They look just like flat packs. anyone with a decent reflow station (temperature controlled hot air) should be able to swap one out without too much trouble. That being said, CPUs rarely go out. I would think its most likely something else. Maybe filtering in the power supply circuit? CPUs are much picker of voltages than LEDs. Just because the proper clock signals are being generated into the CPU, if it is not getting the proper power it's not going to work.

If you are going to throw darts for a repair, start with the capacitors before replacing the cpu. Much easier job. Id scope the vcc line into the CPU for noise/stability. I am assuming you have a oscilloscope if you are able to see the clock frequencies.

 

[levi]

Fair point, I was speaking for people with a temperature controlled soldering iron but no reflow station. I guess someone with an oscilloscope is more likely to have one of those. And yeah, old caps (especially electrolytics) are almost always the first suspect.

 

[Dave18]

Removing the cpu is beyond my skills/equipment. I can manage low pin/low density surface mount only. However I have bought a working unit so I can start to compare signals and see if I can track down the issue. It would be nice to find out why so many of these units are failing (the cpu seems unlikely unless it is being supplied voltages outside set tolerances).

When I get some time I'll start taking some readings.

 

[Steve2019]

Hi, just wondering if you managed to fix your GP32? I have the same problem, its been sitting for a while and now only the led lights up but after 5 mins faint lines appear on the screen. Its a BLU but the backlight doesnt come on either like its not getting a signal.

Tried new AA batteries just incase.

Any help would be great I remember repairing a laptop by sticking the mobo into the oven wonder if its worth sticking the gp32 board in......

 

[renejr902]

Removing the cpu is beyond my skills/equipment. I can manage low pin/low density surface mount only. However I have bought a working unit so I can start to compare signals and see if I can track down the issue. It would be nice to find out why so many of these units are failing (the cpu seems unlikely unless it is being supplied voltages outside set tolerances).

When I get some time I'll start taking some readings.

if you still have it, i would buy it for the LCD Screen. i have a gp32 NLU with a broken lcd screen. thanks