PSone screen problem- screen normal>bright>white>of

bacteria · Post by **bacteria** » Mon May 21, 2007 10:30 am

My PSone screen is working off batteries; 2500NiMH AA rechargables. The screen goes on, image fine, but a few seconds later it starts to get whiter and whiter until it gets completely white, then it turns itself off. It must be getting a signal or there would be no image in the first place.

Anyone know how to stop this happening, and what causes it to happen?

My project is at the final stage, but is useless unless I can solve this problem.

Please help!!

Post by **bicostp** » Mon May 21, 2007 12:01 pm

Did you LED mod the screen or are you using the stock backlight? It may be putting too much of a load on your batteries.

Does it still do that with its power adapter?

bacteria · Post by **bacteria** » Mon May 21, 2007 1:12 pm

No, didn't LED mod the screen.

Not tried it with power supply recently, will do so tomorrow. Does this make a difference? I thought 6 x 2500NiMH batteries (c. 7.5 - 8v) would be enough to power the PSone screen - should I be using different batteries?? This must be a common problem!

All help gratefully received!

Post by **marshallh** » Mon May 21, 2007 3:07 pm

Make sure your LCD's ribbon cable is inserted properly. If it's in sideways or not completely, you will have some weird image problems like you described.

bacteria · Post by **bacteria** » Mon May 21, 2007 3:54 pm

Ok, in morning I will try 3 things in the following order:

1) try the top quality 2500NiMH AA batteries I have - some are Ansmann photo - this will counter issue of battery draw.
2) attach the original power supply for the PSone to the battery terminals and try this instead of the batteries.

if neither works:
3) check ribbon cable - although I haven't removed it and have been careful, so it shouldn't have displaced itself.

4) - no option 4 - is there an option 4?? More ideas to try please!?

I am sure other people must have had this problem too - I will post my findings to the above tomorrow; it will be nice to have a definitive answer, it will help other modders too. Once this problem is cured I can finish my project and post results!

Anyone else had this experience, and how did you cure it??

What type and quantity of batteries do other people use for their (unmodded - ie no LED mod) PSone screens?

c_mon · Post by **c_mon** » Mon May 21, 2007 4:25 pm

I don't think batteries cause the problem; 7.2 Volts is OK for the official PSOne screen. There should be a disconnection or weak soldering somewhere. Also check if there is still video and sound on the screen after the light goes off - that'll help a lot.

Kurt_ · Post by **Kurt_** » Mon May 21, 2007 5:14 pm

Anybody thought "heat problem" yet?

bacteria · Post by **bacteria** » Tue May 22, 2007 1:06 am

Kurt_ - Don't think it is a "heat problem", I thought of this, had a 3" PC fan blasting on the boards and booted, no difference. I have air vents (quite large) to the sides of the PSone board and a gap above the board of about 3mm, with a piece of mounting board on top (flat surface to mount the rest of the electronics. This gives plenty of chance for airflow. Also, I disassembled my project (yet again), same result when components separated.

c_mon - ok, 4th option is I will check my soldering joints. No way to know if the video is on the screen when the light goes off because the light goes off, not sure about sound as I only have a menu showing; however when the problem first started, I was playing a game and the sound went when the video went (during a game). I changed the speakers as the PSone speakers are a bit naff - using old ones I had lying about, 6cm speakers, DYS 8ohm 0.5w - sound is quite good with these (richer and better with lower frequencies, although they are "magnets" - as screen is LCD and not CRT there is no screen distortion of course, so seemed appropriate to use them.

Really hope I can solve this problem, spent many hours in sheer frustration - so close, yet so far!!

bacteria · Post by **bacteria** » Tue May 22, 2007 1:49 am

First thing I did was the battery check - changed the 6 batteries for 2 x Sony 2500NiMH and 4 x Ansmann photo 2500NiMH AA batteries, rather than the cheap ones I got off E-bay from China. 7.5v according to my voltmeter. Booted my (dismantled) project up; first the PSone screen (with the photo batteries), screen was normal and didn't go all white on me, then connected the GBA transverter (with the chinese batteries) - fine again; then the GBA, all fine. Left it on for about a minute. I am having to use one set for the PSone (6 batteries) and one for the Transverter (6 batteries) as on an earlier experiment the batteries got really hot very quickly - 2 sets spreads the load. Thinking about it, this gives grounding for the case for powerful photo grade batteries for the PSone screen.

I have a GP2x too, and know how fussy it is with demanding photo batteries, I suspect the same is true with the PSone screen. Try and use non photo batteries in a GP2x and it probably won't boot up, use standard AA batteries and you get 30 mins max playtime; use high powered photo batteries and you get about 3-4 hours at a push - quite acceptable.

Anyway, time to assemble the unit (yet again) and give a full test. If it is the batteries (ie draw required) then I will have it licked; otherwise back to square one again!

Classic case of trying to save money with (what should be) similar batteries but far cheaper, but not so - the Ansmann batteries cost me about Â£20 for 4, whereas the Chinese ones were about Â£6.50 delivered for 12 batteries. I should have known better! If this rig works this time, it will be interesting to see how long the battery pack lasts before dying; I am hoping to get a couple of hours, but hay-ho.

Hope my hunch is right. Charging up my photo batteries so they are fresh for tomorrow's testing.

Query, guys:

If the battery life I get with photo batteries is poor, I may consider doing the LED mod. I read that this makes the PSone only need 5v instead of 7.2v, would I still be safe to use under 9v after this mod? Would using the LED mod made a dramatic difference to the battery life? (ie does the built-in stock light on the PSone screen draw lots of power)?

If I was (for example) only going to get up to 1 hour on batteries (no mod) but a few hours with the LED mod, could well be viable. Comments?

Kurt_ · Post by **Kurt_** » Tue May 22, 2007 3:18 pm

If the battery life I get with photo batteries is poor, I may consider doing the LED mod. I read that this makes the PSone only
need 5v instead of 7.2v,

WRONG. It still needs 7.2V.

Would I still be safe to use under 9v after this mod?

Absolutely. The voltage needed does not change. Nor does the voltage limits. Only the current.

Would using the LED mod made a dramatic difference to the battery life? (ie does the built-in stock light on the PSone screen draw lots of power)?

It cuts the current usage of the screen in half, roughly. I think it's around 350 mAh after the mod. Maybe 450.

When you say the screen goes white, that doesn't seem to be a problem with the back light, rather the contrast. Keep in mind the LED mod (even with 6 LEDs) results in a darker screen, although it's not horribly dark. I recommend against only 3 LEDs though.

bacteria · Post by **bacteria** » Tue May 22, 2007 3:39 pm

Ok, I don't want a darker screen, so staying with the backlight as is seems appropriate.

If the draw is about 900mah whilst using 2500NiMH batteries, why is the draw on the batteries so strong (surely 2500NiMH should be fine, especially if photo grade batteries (ie designed for lots of quick power drain)? Does this mean in effect that there is little benefit on battery life by the LED mod; only you get a darker screen??

What alternative batteries should I use? (ie what does everyone else use)??

Post by **marshallh** » Tue May 22, 2007 3:44 pm

Unmodded PSone LCD screens draw about 750mA.
LED modded screens (with three 3mm white leds) draw 350mA.

There is definitely a power savings. The brightness difference isn't that bad, if you the jump the capacitor on the back (described in the extremetech articles)

Again, I say this a lot - please don't use AA batteries if you can help it. They simply can't provide the current drawn by a portable. If your batteries get hot, that's a good sign they are being overloaded. Use Sub-c cells or a Li-ion pack.

ShockSlayer · Post by **ShockSlayer** » Tue May 22, 2007 4:54 pm

Replace your speakers. I was working with mine and when a speaker broke it slowly whited out. How quick does it white out? About 10-30 seconds?

SS

bacteria · Post by **bacteria** » Wed May 23, 2007 2:14 am

I am grateful to you guys for your responses. Interesting to see the variety of comments.

ShockSlayer - speakers work fine. I must admit I thought this might be an issue, but they work fine. GBA outputs in mono only, so I split the sound from the GBA speakers (wired directly to these connections and into the PSone), so both channels on my speakers are therefore mono.

Kurt_ - thanks for your comments.

marshallh - I don't have space in my lunchbox (!) for bigger batteries unless I connect both the GBA Transverter and the PSone powered off the same batteries. I spent a while after your post researching higher battery specs (c. 18000mah). If I don't get the results I want from the rechargables I will have to go this route, and makes space in the box for power cells.

Update:

I booted my system earlier, got a few puffs of smoke (oops!), turned off the unit - looks like I had a short of 8.4v via a single strand of wire to the GBA connectors on the on/off switch (3v)! Anyway, corrected this and everything fine - I got away with it! I am using a 4 way on/off switch; one for the GBA, one for the PSone and one for the Transverter - so one flick of the switch and everything comes to life at the same time.

Recharged my photo batteries (Ansmann 2600Nimh photo AA) last night; total voltage is 8.44v (6 batteries). It has been running continuously for over an hour so far; leaving it on "Mario Pinball Land" because it has a demo loop (it is starting to get irritating now!!) - idea is when the screen goes awol I know the maximum I have on the batteries. No point giving system a static screen after all - this replicates playing a game continuously, which is important for this test. I am happy to report (so far) all is perfect, no whitening and screen stable - and the battery pack is very cool - no sign of stress - which was the problem before.

I will post how long it takes before everything dies - if it is over 3 hours I will be quite happy, longer will be impressive!! If this is the case, I will consider project successful and secure the rear of the case to the front, do a few adjustments to the case backing to make it prettier and then paint it. System is currently running with everything intact, on its back but back case not secured to front (in case I need to do anything).

I see now why the Ansmann photo batteries are not cheap, but they are very powerful. Found a link selling them for about Â£13 for a pack of 4 (cheaper in bulk) plus about Â£2 postage.

Perhaps I stumbled on something, other members might find useful! Bear in mind, the batteries MUST be PHOTO ones as they can handle large power drain stress - normal NiMH can't.

I have to use these (or the Sony equivalent) in my GP2x because of the power drain, which is how I knew about this option.

bacteria · Post by **bacteria** » Wed May 23, 2007 3:27 am

(sorry, somehow my previous post duplicated, wasn't intentional).

Ok, results - I got 1 hour and 50 minutes. The batteries started c. 8.4v, checked them after the PSone stopped (sound was still playing, but video off), after this time the voltage dropped to 7.5v. Interestingly, the battery pack for the GBA Transverter dropped during this time from 8.4v to 7.3v too, so getting more playtime by doing the LED mod (not much saving by the sound of it, using 6 LED's for screen brightness) wouldn't save much as the Transverter would only last for a few minutes more anyway!

Neither set of batteries got remotely warm, so they must have had enough juice in them for the job. It doesn't take long to recharge batteries from about 1.26v to about 1.4v each, and the batteries don't have memory leak.

On reflection, I think 1 hour and 50 mins is acceptable, after all, you don't tend to play a handheld console for this long anyway at one sitting. If I decide I need more playtime than this I can invest in a powerpack - although I would in the scenario need to have the GBA Transverter and PSone screen running off the same one (because of space). The other issue is that powerpacks are 7.4v (or bigger/smaller, but don't seem around 8v), which somehow doesn't seem enough - although the mains adapter uses 7.2v, it seems that batteries need over 7.6v before the screen works on the PSone. Just my observation.

Am I right in my observations??