Author Topic: Amiga 500 plus with boot problem (Read 2433 times)

goul · « **on:** February 10, 2016, 10:06:49 PM »

Hi all,

i need help to boot my amiga. I cleaned all chips and replaced the faulty battery with a CR2032 one ( i found a guide for this).

It boot with showing a white screen, but the game get loaded, with video glitches, only if i insert the floppy before power on the amiga but with video.

Oldsmobile_Mike · « **Reply #1 on:** February 10, 2016, 10:14:32 PM »

It's unclear from your post, but I'd start with the following:

What model is it?

If you turn on the power with no disk inserted, do you get the "insert disk" screen?

Does the caps lock light blink?

Are you able to boot off a Workbench disk?

Have you tried with any/all expansions removed?

Possible the CPU may have failed and/or be in the process of failing, if you get an intermittent white screen on power-up. More likely a connection issue, but do you have a spare you could swap in as a test?

jdupuis · « **Reply #2 on:** February 10, 2016, 10:43:02 PM »

Quote from: goul;803809

Hi all,

i need help to boot my amiga. I cleaned all chips and replaced the faulty battery with a CR2032 one ( i found a guide for this).

It boot with showing a white screen, but the game get loaded, with video glitches, only if i insert the floppy before power on the amiga but with video.

Hi!

Like Mike said, remove expansion. Check for Insert Disk Screen.
If you removed any of the chips, check that they are oriented and seated in socket correctly. If you removed Agnus, check that all pins are making contact in socket (none bent over). Check that Denise has no bent pins and is seated. Sounds like it might be Denise and/or Agnus is not seated. Double check your work.

Cheers!!

jdupuis · « **Reply #3 on:** February 10, 2016, 11:15:48 PM »

Hello again!

This may help others as it has helped me over the years: From my Amiga World Magazine. Issue Oct. 1994 page 4 "Denny on DOS"

The screen flash at first power up is actually a series of colors. Fist color is Dark Gray. If it stops here you need to open up and press all chips down firmly in place. Second color is Light Gray. If re-seating chips does not help you have serious problems. Third color is Red. Indicates problem with Kickstart ROM, faulty expansion cards and loose Agnus chips. Try pressing down Agnus. If still no good, try removing expansion cards. Replace one card at a time until you find the problem. Fourth color is Green. Chip RAM problem. Bad memory chip. Fifth color is Blue. Indicates problem with Custom Chips. Again, re-seat or there is a faulty Custom Chip.
On A3000 Desktop. Stops at Yellow. Check Fast RAM Zips. One may not be seated or faulty.

Hope this helps.
Cheers!!

goul · « **Reply #4 on:** February 10, 2016, 11:53:09 PM »

hi again,

@Oldsmobile_Mike
the model is amiga 500 plus with no expansion card
I don't get the "insert disk" screen, just white.
I'll try a wb disk tomorrow, but games boot.
Caps lock doesn't blink.
Rarely on boot up, just a black screen and video signal lost.

@jdupuis
I'll check all tomorrow. However i got the white screen before i removed them.

PS: i attached a "video glitch" example

vince_6 · « **Reply #5 on:** February 11, 2016, 12:22:30 AM »

What type of tv/monitor and cable do you use?
Propably this is not the prob but worth to check it.

If your battery licked on the mobo, perhaps some traces have problems, even if it was sitting with the floppy on top in the closet then perhaps it went to sockets too, even on denise.

I've seen that to a friends A500+ that I repaired.

jdupuis · « **Reply #6 on:** February 11, 2016, 01:11:08 AM »

Quote from: goul;803820

hi again,

@Oldsmobile_Mike
the model is amiga 500 plus with no expansion card
I don't get the "insert disk" screen, just white.
I'll try a wb disk tomorrow, but games boot.
Caps lock doesn't blink.
Rarely on boot up, just a black screen and video signal lost.

@jdupuis
I'll check all tomorrow. However i got the white screen before i removed them.

PS: i attached a "video glitch" example

Check that the braided grounding strap isn't shorting on the keyboard circuit board.
The picture you included looks like it might be Denise. I would not think the Video Hybrid Chip. 500 plus should be rev. 6A. Look over all to see obvious first. Check for mis-cut trace for 2 Meg Chip RAM Mod. Remove 501 Memory Module if you have it.
Cheers!!

Oldsmobile_Mike · « **Reply #7 on:** February 11, 2016, 01:18:33 AM »

Quote from: jdupuis;803824

500 plus should be rev. 6A. Look over all to see obvious first. Check for mis-cut trace for 2 Meg Chip RAM Mod. Remove 501 Memory Module if you have it.
Cheers!!

Above information is incorrect. 500 Plus is Rev. 8A motherboard. Has 1MB chip built into the motherboard, optional 1MB chip in the trapdoor slot. No chip ram mod necessary, and doesn't use a 501 (a 501 is for the regular 500 - only adds 512K - 500 Plus generally uses a different board to reach it's full 2MB of chip).

I would think Denise, too, but it's on the far side of the motherboard - not likely to be affected by battery damage. Still, worth a good cleaning of it's socket.

Hope for OP's sake it's not bad ram on the motherboard...

https://en.wikipedia.org/wiki/Amiga_500_Plus

Oldsmobile_Mike · « **Reply #8 on:** February 11, 2016, 01:23:28 AM »

Pop it open and confirm what ROM chip you have. Stock 500 Plus should have 2.04. Assuming you've removed all expansions, when you flip the power switch you should see a 2.04 early startup screen, the floppy drive should click, and you should be able to toggle the caps lock.

paul1981 · « **Reply #9 on:** February 11, 2016, 02:11:29 AM »

Quote from: goul;803809

Hi all,

i need help to boot my amiga. I cleaned all chips and replaced the faulty battery with a CR2032 one ( i found a guide for this).

It boot with showing a white screen, but the game get loaded, with video glitches, only if i insert the floppy before power on the amiga but with video.

Is this something that's happened since you took the machine apart and changed the battery? Or did you take it apart because the fault was already present and you changed the battery whilst you were in there because it had leaked? If the latter, are you sure your motherboard wasn't damaged by the leak like many other A500 Plus'?

jdupuis · « **Reply #10 on:** February 11, 2016, 02:36:48 AM »

Quote from: Oldsmobile_Mike;803826

Above information is incorrect. 500 Plus is Rev. 8A motherboard. Has 1MB chip built into the motherboard, optional 1MB chip in the trapdoor slot. No chip ram mod necessary, and doesn't use a 501 (a 501 is for the regular 500 - only adds 512K - 500 Plus generally uses a different board to reach it's full 2MB of chip).

I would think Denise, too, but it's on the far side of the motherboard - not likely to be affected by battery damage. Still, worth a good cleaning of it's socket.

Hope for OP's sake it's not bad ram on the motherboard...

https://en.wikipedia.org/wiki/Amiga_500_Plus

Thank you Mike! 23 years - I did not know there was an 8A. I guess when I made the move to my A3000 goofin' around trying to make the A3640 work and OS 3.9, I lost touch with the A500 stuff. Now I'm on to the X1000. Appreciate the heads up!! My A500 Plus was bought from Air Force Base Exchange. "Refurb" yeah! They installed Rev. 6A MB. Guess I was had way back then. $499.00 OUCH!! :lol:

Oldsmobile_Mike · « **Reply #11 on:** February 11, 2016, 04:21:17 AM »

Quote from: jdupuis;803830

A500 Plus was bought from Air Force Base Exchange. "Refurb" yeah! They installed Rev. 6A MB. Guess I was had way back then. $499.00 OUCH!! :lol:

Yikes! I remember going to the PX with my dad way back in the day. First time I ever saw an Amiga, it was love at first sight. Those were the days!

jdupuis · « **Reply #12 on:** February 11, 2016, 11:50:41 AM »

"Yikes! I remember going to the PX with my dad way back in the day. First time I ever saw an Amiga, it was love at first sight. Those were the days! "

Yes they were. Commodore falling apart and pumping last stock out. I think that's how I got the 500 Plus. 1 meg Agnus 512 on board chip and 501 on rev. 6A. (NTSC) That's how they got away with calling it "Plus". A590 with 2 meg RAM coverted to SCSI HD makes it fun. Still love it though. The only Amiga I can turn on a play my boxed games no tinkering!

Amazing how floppies kept in box - in house, have outlasted expectations as with alot of SCSI HD's. They don't make 'em like that anymore.

goul · « **Reply #13 on:** February 11, 2016, 09:49:37 PM »

Hi all again,

few updates.

@vince_6: i just bought an amiga rgb to scart cable replacement for the old amiga 520 adapter. Same screen with the amiga 520, the new cable and composite output.

@paul1981: The fault was present as i connected it, then i cleaned inside and replaced the battery. the battery leaked some acid.

@Oldsmobile_Mike: the board revision is 8A and the rom chip is v2-04. I suppose i can load the workbench (see the attachment). The floppy clicks also with no "insert disk" screen (maybe just a video problem?) and i toggle the caps lock

I'll check and clean denise once asap.

there is a video problem for sure because i saw a guru meditation disapper on boot but clicking the mouse button the amiga has been resetted.

Thanks all.

Oldsmobile_Mike · « **Reply #14 on:** February 11, 2016, 11:31:46 PM »

If you're not getting an "Insert disk" screen, you definitely have either a ROM problem, or a video problem. :rofl: (haha, since you know this already)

I'd revisit that ROM issue, though. When you turn on the power with no disk inserted you should see an "insert disk" screen. Clean and reseat the ROM, or swap it with another one if you have a spare?

Author Topic: Amiga 500 plus with boot problem (Read 2433 times)

goul

Amiga 500 plus with boot problem

Oldsmobile_Mike

Re: Amiga 500 plus with boot problem

jdupuis

Re: Amiga 500 plus with boot problem

jdupuis

Re: Amiga 500 plus with boot problem

goul

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vince_6

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jdupuis

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Oldsmobile_Mike

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Oldsmobile_Mike

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paul1981

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jdupuis

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Oldsmobile_Mike

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jdupuis

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goul

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Oldsmobile_Mike

Re: Amiga 500 plus with boot problem