"Butchered" Amiga 500 Revisited

[@sheep1ewe]

Your channel is criminaly underrated, i am realy happy i found it.

[@JanBeta]

Thank you so much! Glad you enjoy the videos. :)

[@GadgetUK164]

Great stuff! It was certainly worth doing everything you did there to test the serial port. It's certainly not uncommon for failed MC1488 / 1489 when some short occurs on the serial connector. Besides, it made an interesting video topic too! =D

[@JanBeta]

Thanks! I'm probably never going to use that serial port but sure learned some interesting new things doing this. And maybe somebody else can make use of it, too. Plus I have a new tool in my collection for future use. Win-win-win, I'd say. ;)

[@dangwoot]

"Give me some money" - Jan Beta 2017

[@104d_3rr0r_vince]

That's the beauty of old machines. You repair for a month and play for 10 mins... :-D

[@JanBeta]

+Vincent GR Part of the fun, really. :D

[@SproutyPottedPlant]

Nice repair. The Amiga 500 has a really good picture on your LCD, never seen Workbench look so clear! The RF modulator made a mess of it.

[@JanBeta]

Thanks! Yeah, the quality from the RF modulator sucks. The picture looks best from the RGB out on a real CRT though. Much clearer than on the LCD still. :)

[@galois19]

In an attempt to create a serial loopback cable to try to troubleshoot a fault with my A500 Rev. 5 FDD, I managed to reverse the pinout, short the port and sure enough, resistors EMI503 / EMI502 caught fire. I can absolutely confirm that this is what can cause the resistors to fail. Aside, having fixed by loopback cable with the correct connections, I pondered what to do with the male end of the serial cable I had sacrificed. Guided by the Advanced Amiga Analytics software graphical representation of the port test, I created a parallel port loopback cable which seems to pass the tests.

[@andiboy8024]

Hi Jan, ich habe folgendes Problem, beim Start meines Amiga 500 habe ich auf einmal einen grünen Bildschirm und meine Rote Power LED blinkt glaub 9mal und einmal lang. Amiga aufgeschraubt und versucht alles mit Benzin-reiniger sauber zu bürsten. Speichererweiterung hab ich auch entfernt, leider ohne Erfolg.... Kannst du mir vielleicht sagen woran das liegt? Verstehe nicht an was das liegen könnte, habe leider nicht ganz die Kompetenz und das Werkzeug wie du :-). Es ist auch nichts oxidiert oder ausgelaufen. Das Mainboard sieht soweit top aus. Hoffe du kannst mir helfen! Deine Videos sind super, auch wenn es leider auf Englisch ist. :-) Mfg

[@eightbit1975]

Nice videos! Thank you! As an Amiga owner (of a few Amiga computers) I appreciate these videos just in case I ever run into similar issues. Can't say I have a butchered Amiga tho as mine are pretty nice, but good reference nonetheless. Keep them coming! Subscribed!

[@JanBeta]

+eight bit Thanks a lot & welcome aboard! :)

[@MindFlareRetro]

Love this repair. Great work with the loopback cable. Perhaps now you can really go the extra mile and retro Retrobright the keys. Just a thought.

[@JanBeta]

+MindFlareRetro Thanks! I'm planning to do some retrobrighting as soon as there's some more sun here (in a couple of weeks).

[@psyolent.]

ah Jan, i thought i was the only one who tried to test stuff without the power plugged in mate :) again, good job.

[@JanBeta]

Thanks! It happens to me all the time. I'm editing out most of it, though. ;)

[@bamdadkhan]

got to love the old box of hummus in the background : )

[@JanBeta]

Thanks. :) I've been using it for disposing of components while working on something. (The hummus was good, too.) ;)

[@TurumbaTV]

The heartwarming story continues. #saveamiga500 :)

[@JanBeta]

+Turumba TV Don't worry, it's safe for now. ;)

[@GadgetUK164]

Thanks for the shoutout btw! Will return the favour soon!

[@JanBeta]

Oh, thanks! Just had to mention where I got the idea (among a bunch of other good ideas) from. I kind of doubt that somebody watches this who's unaware of your channel but you never know. ;)

[@GadgetUK164]

Much appreciated anyway =D

[@QunMang]

/Me watches video over a year later, raises hand and waves it around. I just started watching this channel, and now I will look at Gadget UK's. Er, after work anyway- I am late heading out as it is...

[@TheHighlander71]

Interesting fact about the com port resistors. Couldn't they have been burned from something connected to the outside? Maybe some dolt soldered his own connector and fried the resistors by putting power on the wrong pins? I wonder if any other issues pop up now with this machine. I guess you've tested it thoroughly by now :)

[@JanBeta]

That's what I'm also thinking. Especially since the ICs were ok. Probably some kind of weird self-made peripheral shorted the power lines to ground. Had this running for a while now with all different sorts of software and it works fine but you really never know. Hope it's fully fixed now. ;)

[@misteragony]

I have the exact same issue on my amiga 500 rev6. So I think it's quite a common problem?

[@kcinplatinumgaming2598]

I watch both yours and GadgetUKS videos for a long time now :D

[@JanBeta]

Nice! I learned a lot from GadgetUKs videos! :)

[@alhartman66]

What software do you use to diagnose problems with an Amiga, and test the RAM?

[@JanBeta]

I recommend using the DiagROM for proper RAM troubleshooting. I'm using the Advanced Amiga Analyzer software in this video which also has various tests.

[@SkuldChan42]

After I finish my repair the Amiga 1200 video - I should try to pick up a dysfunctional A500 for fun and fix it up as well :).

[@JanBeta]

Haha, yes! Highly recommended. Much more fun to work on than the A1200 in my opinion. Plus it's all through hole components! Yay! ;)

[@misteragony]

The burnt resistors are 46 Ohms right? I need to replace the resistors on my amiga 500 (rev 6) and can't see the color coding on the resistors anymore due to the burn marks. Also the two big caps (upper left corner) were leaking so I removed them. The value is 3300µf 10V. Would you advise I replace them with the same value, or is it better to use one rated for 25V for example?

[@JanBeta]

+misteragony The resistors are 47 ohms. I used 1W metal oxide ones, but you can use any type. I think the originals were 1/2W carbon resistors. Using higher voltage (and also temperature) rated caps is always good to make them last even longer. With the higher capacitance ones I tend to use the same voltage rating because they last way longer than smaller caps anyway (in my experience at least).

[@MrRobbyvent]

Have you checked if the new resistors gets hot while testing the loopback serial cable?

[@JanBeta]

No, I didn't. I ran the test for >1 hour though so I'm quite sure everything is alright with the circuit now. Or do you have an explanation why they should get hot with the port working otherwise?

[@MrRobbyvent]

Jan Beta well, I guess because the other ones were burnt You should check if the cause of the burning is still there

[@JanBeta]

+Roberto Ventilii I think the previous owner must have shorted the 12V lines on the serial port to ground somehow. I checked for short circuits before I replaced the resistors. Seems all is good now. :)

[@tenminutetokyo2643]

Replace all those ceramic caps with modern small ones.

[@HBAVHS]

Und schon wieder... ...sehr geil!

[@JanBeta]

+Dieter Löffler Vielen Dank!

[@mark12358]

Very Good!

[@JanBeta]

Thanks! :)

[@philipkirkman9760]

Nice one :)

[@JanBeta]

+Philip Kirkman Thanks! Still works fine today. :)

[@alynicholls3230]

those "resistors" are inductors, desolder a good one from a working board(can only get accurate reading out of circuit) and measure it on L(inductance)mH, the bands on those type of inductors are not as reliable as true resistors.