Leo's weblog

Replacement PLA for C64

One of the C64's I have would not boot. The led came on, but the screen remained dark. I swapped the PLA chip 906114-01 from another C64 and it then worked OK. If you search for this chip you will notice that it's quite expensive. That's because, like the SID, it will go bad at some point in time. So it becomes rare.

Several alternatives are available and I chose the Commodore C64 PLA 906114-01 redesign with M27C512-90B6 EPROM from Vintage Computers. I also bought the SwindSID from here.

I received the PLA this week, installed it and it works fine.

PV544 out of storage

This week I moved the van into storage and the PV544 out of it.
There was some work to do: The indicators were very weak and the windscreen washer did not function at all. As these functions are mandatory at the periodical legal test so I had to repair these immediately. This is a 6V car you know...

I cleaned some ground wires at the battery and the fusebox and all was well with the indicators, but the control light on the dashboard did not work. I tried to repair the flasher but eventually it got bad. So I ordered a replacement, which is also suited for LED's. I may replace some bulbs for LED's if that is going to work with 6V.
The gears in the pump for the washer were full of lime and I had to dismantle it fully to get it functioning again.

A500 Plus Rework [2]

I have replaced the socket for Gary. When I try to boot the A500 Plus I immediately get a green screen, which means Bad RAM. But it can also mean that the RAM isn't accessible, because of for instance a bad Agnus or Gary. So I rechecked the traces coming from Gary. I couldn't find any fault. As I cannot think of any other cause I will leave the machine for the moment. I might buy an A500 Plus board I saw for sale.