Re: Commodore 128 Startup advice

Hi Ruud,

Thanks for the reply. It has me confused also as I am now finding it not to be entirely reproducible.

Yes I am working in 40 column mode ... I do have the capability to go to 80 column but only using the luminosity channel at present.

I tried the C128 the past two mornings and it boot fine ... just tried it now and got garbage screen ... hit the reset and works fine again.

Will try swapping the CIA chips and again reseating all the other ones. Will get back to you.

I don't have any replacement parts for the unit.

Andy

> On 8 Mar 2017, at 16:26, Ruud@Baltissen.org wrote:
> 
> Hallo,
> 
> 
> I'm a bit confused. First you say the C128 boots fine in 128, 40 
> column config, then you say it won't, that is, from cold.
> 
> You didn't mention the 80 columns screen at all so I can assume you 
> are talking only about the 40 columns mode.
> 
> My first problem: I got my experience for repairing computers by 
> using the try and error method. The actual problem: I hardly ran 
> into brooken C128s. The most common failures: RAM and CIAs, and in 
> one occasion a ROM.
> 
> It boots fine in C64 mode so we can rule out the first 64 KB of RAM 
> anyway. If possible, swap the banks and see if it boots fine in C64 
> again. If so, you can rule out the RAM. If not possible, the C128 
> uses the second bank for BASIC and IMHO won't affect the boot 
> process. 
> 
> Recapping is not needed IMHO as bad capacitors cause problems 
> randomly, not just at boor up.
> 
> Once booted up in garbage, have you tried to enter commands like 
> DIRECTORY? If it is just a screen problem, the drive should start to 
> rotate. One thing you can do is to replace the CIA serving the IEC 
> bus and userport. If you don't have an extra CIA, swap the two on 
> the board. And then boot the computer.
> 
> The boot problems could be caused by a flaky ROM. Whatever you have, 
> replace the for sure. (easy for me to say because I have tons of 
> them laying around).
> 
> Just trywith what I gave and let me know what happened.
> 
> 
> --
> 
> Kind regards / Met vriendelijke groet, Ruud Baltissen
> www.Baltissen.org
> 
> 
> 
> 
> 
> 
> 
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