Fantazia refurb

[Dax]

Firstly apologies if this is in the wrong section.

Here are a few pics of our newly acquired machine.

And the worst bit

clearly there is an issue with the board, Since getting this machine we have done a few things to the board to attempt to remedy it but neither myself or Lookmumnocomputer (Sam) have any arcade specific knowledge.

Things done so far

A lot of the ram chips on the top right of the board were missing legs due to corrosion and have been replaced and resocketed as required.

All electrolytic caps have been changed on the mainboard and in the power supply board.

with zero knowledge we are now a bit stumped as to what our next step should be, we do have access to oscilloscopes and bits of test equipment.

Any pointers or advice would be greatly received

A huge thankyou in advance.

 

[NivagSwerdna]

If you look in the FixLog section you see I am playing with the same board at the moment... I would be very interested to know what you have in your colour PROM.

I cannot really tell from your image if that is being displayed or is just burn-in.

 

[Dax]

That is being displayed, the crt doesnt appear to have any burn in at all.

I saw your fix log and read through it with great interest.

 

[NivagSwerdna]

Well to get that far a lot of things must be doing a lot of things right!

With two things... a PCB and a Monitor... there are between zero and two things that can be broken... Do you have a way of testing the monitor or PCB in isolation?

The fact that it is rendering the welcome screen and it is synced really shows that the majority of the text side at least is working. The fact it is monochrome perhaps suggests a problem in the final stages which is really only the colour PROM and the monitor itself.

Obviously you should do the basics first... voltages!

NivagSwerdna2022-08-08 15:15:20

 

[Dax]

Yes i will check the voltages at the main connector for the board. its not monochrome either just very green there is other colour there but alas my phone camera didn't do it justice.

Unfortunately we have no way to test either the crt or board separately.

 

[NivagSwerdna]

You said you had a scope... have a look at the RGB signals coming out of the PCB... see if they look lively or droopy.

 

[Dax]

I'll be at the Museum tomorrow so will grab the voltage readings and also get some pics of an oscilloscope hooked up to the outputs of the RGB.

Is there anything else i can take a picture of or video to help resolve this ?

 

[Dax]

The 5V line has exactly 5V, the 12V line however seems to be only outputting a few millivolts, double checked the psu board and there is indeed no 12V.

I'll get the 12V working again and get back with any changes.

 

[Dax]

Well i checked and double checked and as far as i can tell the board has no actual 12v connection so its only using the 5v line i guess.

Trying to find something at the museum that outputs a scart rgb signal as i can feed that into the monitor to test it.

Had a bit of an issue with various oscilloscopes today, some powered on but didnt work, a couple didnt even power on and 1 decided to power on and work for about 30 seconds before letting the magic black smoke out before dying. i'll spend some time next week either fixing or finding one that workss so i can test the rgb output.

 

[NivagSwerdna]

How did this go?

I have my board working now so could probably look at yours if you were interested?