Retrobright experiment 1.0

[dirkwhoffmann]

Those two cute puppies just arrived 😃.

Both must have manufactures in different years, because the labels are different. If I remember correctly, my own Amiga looked like the one on the right (with a Commodore logo, but no text label).

When I switch them on (with the 30 year old power supply still working), the power led turns green and I can hear the drive head clicking. This is pretty good, because it means that a whole lot is still working (e.g., CIA A timer interrupts to do the drive clicking). Unfortunately, I cannot test video output at the moment, because the RGB cable hasn't been delivered yet.

I’ve already got the Gotek drive though, but I’ll wait to replace to original drive until I can confirm that Denise is still on duty.

If you look at the pictures more closely you might notice that both must have played in the mud for a longer time 😳. Seems like they should take a bath first (haven't gotten a shower for 20 to 30 years I guess 😲). I’ve already ordered hair bleaching creme to apply some retro brighting on the plastic parts and I am curious to what degree both can be optically restored. Before doing that, however, I should wait for the RGB cable to arrive 😴.

[mithrendal]

There is one excellent thread about cleaning Amigas on EAB. Especially removing the yellowing. It gets really chemical there ... Maybe some more stronger weapons than your bleaching creme ? Some methods I don't dare they look frightening to me. But interesting to see those sucess pictures of how an treated Amiga could look like after those cleaning procedures ...

http://eab.abime.net/showthread.php?t=37808&highlight=lemonade&page=7

!!! Attention: be prepared, the nerd factor is extremely high !!!

[dirkwhoffmann]

Uhhh, that thread is loooog. Need some time to read it through.

The current standard approach seems to be

• apply hydrogen peroxide in creme form.
• wrap everything in foil.
• expose it to sunlight for a day or so.

I bought two big bottles of "M:C Cream Oxide 1000ml 12%". It's supposed to be applied on hair, but most Amazon reviewers used in on their computers instead.

There is also a cool video here about retro brighting:

https://www.youtube.com/watch?v=qZYbchvSUDY

[mithrendal]

Oh from the 8-Bit Guy, cool I saw some other of his videos before... The final result of his retrobrite treating is looking very good. Must work with your two "new" Amigas too. 😊

[dirkwhoffmann]

Getting smarter...

http://www.lemonamiga.com/forum/viewtopic.php?t=3195&sid=0ab1d0ff902e428ceaf78aa962799843

"There are 4 different kinds of labels: 

1) the square one moulded into the case: 
This one is very rare and only found on the first Amiga-500s. Most of them still have kick 1.2,
and some very early ones also have a different keyboard with lower keytabs and a C= key on
the left side insted of an 'A' key. 

2) the standard square one: 
this is the most common one and was used on A-500s from '88 to '91, I think. 

3) the rectangular one (without PLUS): 
These were the last A-500 made. I think the label was changed when the A-500+ came out,
but I am not sure. Some of these also have an A-500+ board inside, but only equipped with
512KB instead of 1MB onboard. 

4)the rectangular A-500 PLUS one: 
looks like number 3), but has A-500 PLUS written on it."

This means I am now the proud owner of a number 2 and a number 3 Amiga. The left one is the "newer" one (although more yellowed). I am curious if they both use the same Kickstart. If I'm lucky I have one with Kick 1.2 and another one with Kick 1.3.

[mithrendal]

Oh look and there is already a teardown on the net for the Amiga 500 (Type 1)

https://inkoovintagecomputing.wordpress.com/2018/01/18/amiga-500-teardown/

Result: repairability and upgradability 10/10, no pentalobe only phillips screws, no glue found and yes you can swap easily some more memory in and swap the CPU as it is not soldered on the mainboard. 👍🏻

[Alessandro1970]

Do they need to be recapped ?

https://www.youtube.com/watch?v=oMqQxSzQxII

[mithrendal]

Dirk will see whether they are still working when he connects them to a monitor. I read on EAB that when everything works there is no reason to recap as it also inherits a risk of doing something wrong in the recap process. I read that A500 capacitors are far more solid compared to those in a A1200. I also read that it is more urgent or to say mandatory, to check the trapdoor expansion for a battery clock as this battery could eventually leak and destroy the mainboard.

[dirkwhoffmann]

The teardown is very useful. I'll try to disassemble it tomorrow to get the plastic parts apart.

I'll do the old model first to get some practice. Overall, the newer models seems to be in a better shape, despite being more yellowed.

[mithrendal]

Amiga Hardware Database which lists all mainboard revisions of the A500 http://amiga.resource.cx/mod/a500.html

according to that the newer is maybe Rev6 or Rev8(already supporting ECS) and the older is probably Rev5 (OCS). Already so curious what dirk got there for exemplars ... ;-)

[dirkwhoffmann]

Let's open up the older mode. Here we go:

Some corrosion on the shielding, but I think it looks worse than it is.

Removing the keyboard was a piece of cake. Removing the keys from the keyboard was a little tricky for the larger keys, but I finally succeeded to remove them all without causing damage.

This is after cleaning:

The keyboard mechanics of the Amiga seems to be of really high quality, much better than the awful butterfly keyboard of my costly MacBook Pro (which is faulty by design).

Now, let's look at the mainboard:

Now we know: I've got an A500 rev. 6A 😃.

I've spend all morning to remove dirt from the case and the keys and couldn't start the bleaching yet, because we it's pretty cloudy outside. I'll have to wait for the next sunny day.

The motherboard is also pretty dirty, but there seems to be no corrosion on it. Hence, with some pressured air and contact spray (which I need to order), I think it can be put back in a pretty good shape.

The drive doesn't look very well, but I'm going to replace it by the Gotek drive anyway.

[mithrendal]

Yep I have spotted the Fat Agnus 8372A (part of the ECS chip set) supports 1 MB Chip RAM. According to Amiga Hardware Database. I can see the 512K Chipram is soldered on the mainboard. I also see there is still space for another 512K. That sets this Amiga apart rom its older brothers out there. It maybe already supports the new ECS resolution modes?

[mithrendal]

According to this article you may not need to clean the corroded shielding. You could use the A500 without it and give the shielding into the recycling...

https://retrocomputing.stackexchange.com/questions/1479/is-the-metal-shielding-required-in-all-in-one-amiga-models

[dirkwhoffmann]

After a one hour bath 🤢:

This guy has seen better times I guess 🤭:

[dirkwhoffmann]

Agnus in more detail:

Behind the dust is Denise ...

It's the standard 8362 R8 revision. I think for ECS, a 8373 is needed.

[mithrendal]

What about the mouse ? And the 🕹 Joystick? (My old ones are lost, maybe also given into the recycling (but not by myself 😢))

[mithrendal]

8373 is maybe in the other brother. That would be perfect we have different versions of Denise then.

[dirkwhoffmann]

I still have my two old Competition Pro II's (unfortunately, I hammered the right mouse button so hard 30 years ago that only the left button is still working). I regularly use them with a retro Joystick <-> USB adapter to test VirtualC64.

Regarding the mouse, I've ordered a Amiga mouse <-> USB adapter from Vesalia. Should come with my RGB cable. Delivery seems to be slow though. My order status says "Waiting to dispatch" for 5 days now 😖.

[dirkwhoffmann]

A sunny day, perfect conditions to do some retro brighting 🧪:

Unfortunately, it is more complicated than I though. It's not so easy to distribute the bleach uniformly and wrapping everything into foil sounds easier than it is, too. The slightest gust of wind messes things up.

I have to wait for a couple of hours now, but I expect that I'll need to do it again 🙁.

[MrStargazer]

We are hitting every minute F5 ....for hours now ... so eager to know if the hairdryer helmet process is ready already and the "hair" is bleached to gold now. 🤤

[dirkwhoffmann]

We are hitting every minute F5 ....for hours now ...

Oh, I was busy disassembling the other Amiga 🤤.

Let's see what we've got here...

Interestingly, the keyboard is completely different. This one is from Mitsumi and has real springs. The old model has a Samsung keyboard which seems to be of higher quality.

Let's get rid of the keyboard...

It really is a little bit tricky to remove the board from the lower cover... oouups....ouch 😬

So heartbreaking 😢. Promise me not to tell anybody, OK?

OK, back to the board. As Mithrendal predicted, it's a rev. 8A Amiga 😀. Denise is the same as in the old model though.

Overall, I think I was very lucky with this A500. Although it is really dirty and very yellowed from the outside, it looks pretty good from the inside. The logic board looks like out of the shelf, manufactured a week ago or so. I think the original owner didn't use this model much. It does not even have a Ram expansion and the trapdoor looked like it had never been opened. On the other hand, the key caps were really 🤢.

In half an hour or so, I'll see how the brightened case and keys look like. Stay tuned 😎.

Oh, I just got confirmation that my RGB cable and mouse adapter is shipping 😀.

[dirkwhoffmann]

Here is the (mixed) result. The keys look pretty good as far as I can tell at the moment:

It didn't work so well with the case though. I now have an A500SE (Stripe Edition) 😂.

Tomorrow, I'll try again. The question is: What should I change to get a better result 🤔?

[mithrendal]

Dirk. What is exactly the liquid where you put the key in ? I guess the stripes are because the thickness of the cream was not the same everywhere ? Maybe there, where it was more thick, it is now more white?

In the video of the 8-bit guy you referenced, at position 16:10 Minutes he put the case into a bath of hydrogene peroxid for 6 hours at a temperature of 58 celsius and exposes that to the sunlight. Don't you think that this will give you a more evenly result of bleaching? A bath has not the problem of different thickness.

[Alessandro1970]

I’ll follow you... Amiga 2000 tear down...

...battery dead ...removed

[dirkwhoffmann]

Awesome!!! Now we bring all our old Amigas back to life 😃

The battery was here, right?

By looking at the mainboard, it seem like the Battery didn't cause any damage, did it? Have you tried booting? However, it might be safer to check the power supply first...

For my two A500's, I have ordered a replacement power supply, because I don't trust the aged original any more. At least I don't want it to be switched on without having a close eye on it.

With an A2000, it should be a piece of cake to integrate a Gotek drive, because of the standard drive slots. That's more tricky with the A500.

[Alessandro1970]

HI, Yes, there it was the orrible battery...

I removed the battery due to acid leakage. I cleaned but under the battery two electric tracks are badly visible ... How sad ...

Turns on and shows the kickstart, there is 3.1 (I would like to restart the kick 1.3)

If I could replace the various chips and update them with better versions I would do it willingly but at the moment I don't know which ones to replace. Strange that FAT LADY is written in place of Fat Agnus.

Today I send the MOBO to 300km from me to do a complete RECAP and insert a better battery.

[dirkwhoffmann]

I guess the stripes are because the thickness of the cream was not the same everywhere ?

Yes, it must have to do with the thickness of the creme and maybe, the crumpled foil at some places (which hinders light to come through, I think).

I'll do some experiments later (it's going to be another perfect retrobighting day in my area).

I am using this creme:

The water bath in the 8-bit guy video makes sense. However, the creme is easier to apply (e.g., I don't have a big enough container where I can put the liquid in and I don't know how to get rid of the stuff after bleaching). If I blonde the grass, I'll get into some explaining troubles. I also have to watch the neighbour's cat which roams around all day and walks over and into everything it doesn't know. If the cat gets blonde, I'll be in real trouble 😬.

[Alessandro1970]

... do you know where someone sell a new PSU (or a good one) for amiga 2000?

You can buy it if I confirm the functionality and success of the MOBO recap.

[dirkwhoffmann]

Turns on and shows the kickstart, there is 3.1 (I would like to restart the kick 1.3)

You can buy replacement Roms for a low price. E.g., it is offered here for under 10 EUR:

https://www.vesalia.de/e_kickstart[8908].htm

[dirkwhoffmann]

I've ordered this replacement power supply (not so cheap though):

https://www.vesalia.de/e_apower[9268].htm

[dirkwhoffmann]

Oups, just seen that it is not for the A2000

[Alessandro1970]

My Amiga 2000 has the OCS but shows 1MB Chip RAM ?! So, can the OSC manage 1MB chip ram ?

MOBO rev 6.2

[dirkwhoffmann]

As far as I know, all A2000 shipped with 1 MB Ram on board (512 KB Chip + 512 KB Slow). The upper 512 KB are the same you add when using a A500 trapdoor Ram expansion.

[Alessandro1970]

Amiga 2000 with rev 6.2 or upper have 1mb chip ram

[dirkwhoffmann]

Another round:

This time I think it works better. The case of the Hong Kong model (rev 8A Amiga) seems to react quiet well to creme and sun. The keys seems to be more difficult though. For the German model (rev 6A Amiga) it was the other way around. The stripes are still there, but it's improving. However, I fear that I will end up with a white A500 eventually.

[dirkwhoffmann]

Here we go 😎.

Lessons learned so far:

• The Amiga is not really meant for wide screen displays 😲.

Now I have to figure out how the Gotek works. In the current config, I simply connected the old drive to make Kickstart happy during boot.

I'm glad that bathing the motherboard in contact cleaner this morning didn't do any harm. It looked like a wet dog after spraying 🙄.

[mithrendal]

I simply connected the old drive to make Kickstart happy during boot.

confused 🤔... A500 must not boot kickstart ... kickstart is in rom ... or do you mean that kickstart does not process until the hand is not shown by kickstart unless a drive is connected ???

So glad that the RGB Cable connection works well. 😊Picture looks crisper than my A1000 composite out signal.

the Amiga is not really meant for wide screen displays

do try to force the monitor in 4:3 via monitor-menu.

In my opinion on the picture fat Agnus looks not so clean yet, don't you want to gently brush its surface? 😎👌But don't rub of the text and numbers though.

BTW: your other A500+ Rev8A looks sooo clean and new from the inside unbelievable...

[dirkwhoffmann]

I've got the Gotek drive working.

Configuring the monitor in the menu worked, too. The wide-screen LCD has enough space for 2 Amigas 😅.

Mouse and keyboard also work 👍. Only the sound is scrambled. I can hear it, but the quality is really low. Logical reasons tells me that it cannot be Paula, because I wouldn't hear anything reasonable then. I guess it's the corrosion of the two audio outputs that scrambles the analog signal.

[mithrendal]

I guess it's the corrosion of the two audio outputs that scrambles the analog signal.

do a cross check with the other A500+ mainboard. (as sound check use the rink a dink demo)

[dirkwhoffmann]

Results of second round:

Hong Kong model looks pretty good 😋 (some light stripes though):

German model still has stripes (but much less).

I'll start a third round tomorrow, because I have to redo the keys anyway.

When playing around with the original Amiga, I miss vAmiga's "load with warp speed" feature. This really accelerates things quite a bit.

[mithrendal]

Is the gotek drive not any faster then the original drive?

[dirkwhoffmann]

Is the gotek drive not any faster then the original drive?

It can't be. Maximum transfer rate is 3 words per rasterline (because there are 3 DMA slots reserved for the disk controller per rasterline). This maximum limit is already reached by the standard drive (almost).

[dirkwhoffmann]

Just checked the newer model. Everything is working fine except the Mitsumi keyboard. At first, I thought the keyboard is broken, but I guess it's just a physical issue due to the old-fashioned mechanics with springs. If the keycaps are removed, the springs have to be removed as well. Therefore, all keys fall down and have contact, so I'm actually pressing all keys at the same time. I'll have to try again when the keycaps are restored.

Sound of the new model is 👍, so it's not an issue with the cable or the HDMI adapter.

Here is how the audio plugs of the older model look like:

I am not an expert in old electronic parts, so I can't judge myself if the visible corrosion is enough to cause the issue.

I also took a picture of the internal contacts:

I've got another problem, though. When I put the computer back in the case, the drive cables are much too short to connect the Gotek. Besides, I would have a strange looking cable coming out through the disk slot to connect the drive externally. To solve this, I've ordered a second Gotek from Spain which is ready to be installed inside the A500. I've also order an adapter cable, so I can use the first Gotek as df1:. Oh man, this hobby is getting costly 😦. Nevertheless, it's a lot of fun 🥳.

[mithrendal]

Wow, SoundConnector side of the old board is looking like an old star wars space ship after tons of years of being in da space and after countless times beeing under fire from hilarious grunting aliens 🐗. And yes the WAF too is very very extremely low. 🙊

[dirkwhoffmann]

like an old star wars space ship after tons of years of being in da space

That would explain all of it! Maybe it was on a space mission in its former life. Perhaps I should check how the audio jack connections look from the lower side of the board. Unfortunately, I need to remove all connector screws for doing that. Not sure if I have the right tools for doing that...

And yes the WAF too is very very extremely low.

Well, yes, I can confirm this 🙄.

[dirkwhoffmann]

Oh no, I screwed it up 😳. None of the dark keys survived the "procedure" 🙈:

Now, I have an A500 CE (creme edition).

[dirkwhoffmann]

This morning, I recognised that my Retrobright project has ended up in a disaster 🙈. The marble look is not only on the keycaps, but on the cases, too.

Here is the thing: When the keys are wet, they look almost perfect:

When they dry up, the marble look reappears (as in the picture in my last post). The same holds for the cases. When they are wet, they look good. The dryer they get, the worse they look.

I've come across this picture in the internet which shows a similar problem with an old Mac:

https://68kmla.org/forums/index.php?/topic/30384-retrobrite-fail/

The guy used headlight restorer to "rescue" the screwed up keys and another one suggested to use 1000 grit wet sand paper. I can try that, because the cases and keys seem to be ruined anyway.

Nevertheless, I think I have to watch out for other Amiga cases on eBay 😢.

[mithrendal]

In my opinion the cause of the marble madness is the method with the creme and foil. Trust me.

1. I would strongly suggest to do the bath method with the marbled cases and keys as detailed in the video of the 8-bit guy you referenced, at position 16:10 Minutes ! As this will bleach out the marble pattern. The only risk will be that it will come out maybe a bit whiter than it original was, but my strong opinion is that the marble pattern will bleach out evenly and vanish. And get a transparent plastic box for this not a colored one as the 8-Bit guy. I am sure that it will repair the marbled madness ;-) And forget about the cat. You must set priorities now in this serious situation you are in now.
2. I would never do the sandgrit as you would definitely ruin the haptic feeling of the case and keys.

otherwise I would it leave in the current condition at least it is super clean from a hygienical point of view.

[MrStargazer]

Why feeling so negative about the result.

For me it looks like an Amiga 500ME (Military Edition) now.

[MrStargazer]

Maybe the sandgrit can help you to get rid of the scrambling sound.

Just polish the outside of the corroded cinch pins. I think it is worth a try.

[dirkwhoffmann]

Maybe the sandgrit can help you to get rid of the scrambling sound.

I used a fibreglass pen to clean it a little and applied some contact spray. I didn't reconnect the board, so I don't know yet if it solved the problem.