A500 - Restoration Project

[1NOM155]

Hi Amiga Fans,

This its my project to restoration of a 3 Amiga's 500.

There is the 1st couples of pictures. Will post more when trough the project.

This its the state of the shields (I didn't take more pics ):



After metal work (that box bring some good surprise:


(missing one of that small shield to cover the Zorro / External expansion, if someone have any to sell or know any company who can make one, please PM me.

Ram expansion:

How it was,
View attachment 81278

Some progress:

View attachment 81279

(this its another ram expansion I have to repair, on the next pictures I fit one ram expansion it's in good condition bought from user Chapas)

The assembly:





To be continued

PS: I need some help / tip. I discovery when I connect my DF1 (External Floppy - Cumana CAX-354) there is some interfering / fading image. Its a sing may need to swap caps? I ask that because rather then that, I don't have any issues (playing games / audio).

 

[Firthy2002]

What PSU are you using?

 

[BLTCON0]

PS: I need some help / tip. I discovery when I connect my DF1 (External Floppy - Cumana CAX-354) there is some interfering / fading image. Its a sing may need to swap caps? I ask that because rather then that, I don't have any issues (playing games / audio).

The +5V voltage on A500's is rarely higher than 4.75 - 4.80 V in practice inside the motherboard. The CAX-354, being a slimline drive, only uses the +5V line and thus taxes the +5V line more heavily, causing sudden voltage drops and resulting in the fading you notice when it's in use (even just clicking, it can cause fading).
Using a "true" A1011 Commodore drive will give better results, as it uses both +5V and +12V thus lowering the +5V load. This, I've tried and seen.

I don't think changing the caps will cure anything, but maybe cutting the power cord to half the length will cause less of a voltage drop. Haven't tried that, but I have converted an ATX PSU with the full length cable from the original PSU and the voltage is still around 4.75 V and the fading is of course there with slim drives.

 

[1NOM155]

Humm interesting.

My PSU have 4.3A 5v 1a 12v and 0.1a -12v.

Also I looked some issues in video using a RGB -> SCART made my Retro Computers Shack. And the video hybrid version rev 1. I think still need to recap motherboard and psu.

 

[roy_bates]

Humm interesting.

My PSU have 4.3A 5v 1a 12v and 0.1a -12v.

thats the heavy transformer type isnt it? dont discount there might be something wrong with it...unless its fine with other amigas with an external floppy.


also,i think i have a spare sidecare cover you can have...ill have to have a look and see where it is though.

 

[BLTCON0]

I think still need to recap motherboard and psu.

Let us know how it goes, I'm curious if it makes any difference.

 

[1NOM155]

Humm interesting.

My PSU have 4.3A 5v 1a 12v and 0.1a -12v.

thats the heavy transformer type isnt it? dont discount there might be something wrong with it...unless its fine with other amigas with an external floppy.


also,i think i have a spare sidecare cover you can have...ill have to have a look and see where it is though.

Hi mate if you have a "sidecar" metal cover please PM me
About the PSU yes its the heavy one, I have another's but I didn't test them.

I think still need to recap motherboard and psu.

Let us know how it goes, I'm curious if it makes any difference.

About the recap I think its better to recap everything (mobo's and PSU's) they are very old and haven't be connected for too much long time.

When I finish the recap I'll share the pictures.


BTW, just for the curiosity, should I use the same Electrolytic capacitor, or Tantalum caps, or even ceramic non-polarized capacitors?
I don't know if using that can I correct the mistake made by Commodore, polarizing in the wrong way (or that didn't happen in A500 6rev)?

 

[britlord]

You need to make a PSU unit like this my friend. +5v 15 amp, +12 6 amp, -12 .03 amp. Total output is 150 watts...Plenty enough for all the Amiga add-ons too.. (I have converted 2 of these AT PSU so far)

Oh, in my 500+. I have mostly have Tantalum caps. Except for the three 330uf ones....

 

[1NOM155]

You need to make a PSU unit like this my friend. +5v 15 amp, +12 6 amp, -12 .03 amp. Total output is 150 watts...Plenty enough for all the Amiga add-ons too.. (I have converted 2 of these AT PSU so far)

Oh, in my 500+. I have mostly have Tantalum caps. Except for the three 330uf ones....

Humm nice, I have spares AT and ATX PSU's but I can't find the special Amiga connector. I don't want to destroy an Amiga PSU to get the connector.
Anyone knows here I can find it?

 

[1NOM155]

After a couple of tests, the problem was in the PSU
My dilemma, after testing the caps with a multimeter without any issues, and with another PSU, everything its ok, should I change the caps on the mother board?

 

[1NOM155]

Today I receive the shield form great Roy_bates , I didn't take a picture but fit like a glove.

About the ram exp, unfortunately I don't have good news, after replacing the components, except the ram and clock chip (RTC), still don't work / recognized.
Plus freezes the system after a couple seconds of turn the machine on, I only can see the Kickstart image and then grey screen.

I'm think to start making a new exp from scratch base on 501 schematics.

 

[1NOM155]

New update:

recap on a Chinon FB-354:



recap and battery change on a 500 mem exp. and made some tests:



I'll update with more photos soon as I can