Hello everyone

The seller was super nice about the refund.

Not only he did a full refund and he asked me to keep the modules in case in the future I get access to a 6volt board.

I promised him to compensate for his kindness if I can get it to work.

I did remove the CPU and the eprom from the sockets and used contact cleaner spray plus air to dry. After carefully reinserting the
chips the same issue persists. Random lights flashing on the board and module. And garbage characters on display.

I am going to try to purchase a CPU from ebay and if possible a replacement programmed eprom from a member here if any one is able to sell me one.

I feel bad for the seller to be honest.

I will try to post pictures here.

Thanks for looking in to this for me all.

Murat

Hello Andreas.

Here are the pictures you requested.





I did clean the sockets and re inserted the chips. Did not see any
broken solder points.

Thanks again

Murat

This looks a bit strange.

Miniaturansicht angehängter Grafiken

 

You are right Udo,

there is some damage done by soldering there but I was
thinking it is part of the modification to use a bigger eprom
for the integrated HG 550. perhaps I am wrong.

I am adding a close up for that area.





maybe we got something

Murat

That would probably have to be measured.

I know something about it, but I'm not an electronics engineer.

Thank you for pictures.

CPU is rated at 3 MHz, so in MM V it is overclocked by approx. 65 %... Not unusual for devices designed by H&G. And not likely to cause the problem.

Yes, some solder eyes look odd.

Ideas:
Incompatibilty with your modular board. Try another one if possible.
Eprom could be corrupted.

Do you have other modules oder chess computers with 65c02 inside? If you buy a CPU on ebay... you don't know whether it is working or faulty.

I would try:
another modular board
new Eprom
another CPU

In this order.

The "problem zone" with corrosion (!) has nothing to do with HG550 modification.

Some part of modification you can see in the upper-left corner of the first picture. There is a region of three solderpads. The connection of middle and right pad is opened and left to middle one has been soldered.

Ich würde das Teil wenn möglich zurückschicken.

I would send the part back if possible.

Sadly I do not have another modular board to try.

These 2 points on the board have a hairline connection. Do they have to be connected nor not in your experience?



Eprom corruption is possible because when I first opened the module, one side of the Eprom was slightly raised but of course I had already tried to run it.

If any member in the forum is willing to help me with a
pre programmed eprom, I will gladly pay for it.

If I purchase a new 65C02 from ebay, does it matter
if the speed is higher then 3MHz or try to get the same speed.

Thanks again everyone.

Murat

You should clean everything a little and then rework the critical soldering points with a soldering station, not with a normal soldering iron at mains voltage! Static Overvoltage possible.
However, the right of return would then expire.