Search found 109 matches

by banman
Mon Sep 07, 2020 10:17 am
Forum: Hardware
Topic: Adrian's RF modulator video cleanup
Replies: 9
Views: 1109

Re: Adrian's RF modulator video cleanup

Hi rmzalbar,

No stress. I hope you are well in these uncertain times.


Thanks for the information. I will have a good look at this.
I would like to get the audio going thru the RF section again.

It must be a relatively easy fix. The SID chip works fine using the the 8 pin AV connector.
by banman
Mon Aug 31, 2020 4:21 am
Forum: Hardware
Topic: The Dos and Don'ts of using an EPROM as PLA in a C64.
Replies: 97
Views: 9860

Re: The Dos and Don'ts of using an EPROM as PLA in a C64.

Hi Zibri, I would say there are undoubtedly other candidates for an E/PROM based PLA substitute. I believe eslapion sells a PROM PLA replacement called sPLAtt. It uses 2 x ST's M27C256B-90B6 and some associated hardware. https://www.melon64.com/forum/viewtopic.php?t=2445&start=30 Ray Calsen has mana...
by banman
Sun Aug 30, 2020 5:41 am
Forum: Help!
Topic: 4264 vs. 2164 RAM chips
Replies: 16
Views: 3022

Re: 4264 vs. 2164 RAM chips

Hi Gyro Gearloose, Yes, I just tried several of them. I can say they work fine. I am surprised they work considering the manner they were stored in for 30 odd years and how I was handling them recently. I must say I didn't realize they were CMOS style until I started looking up datasheets. I tried t...
by banman
Sat Aug 29, 2020 5:55 am
Forum: Help!
Topic: 4264 vs. 2164 RAM chips
Replies: 16
Views: 3022

Re: 4264 vs. 2164 RAM chips

Hi Gyro Gearloose,


Okay, good. Thank you for the information.


I'll get back to you.
by banman
Sat Aug 29, 2020 4:52 am
Forum: Help!
Topic: 4264 vs. 2164 RAM chips
Replies: 16
Views: 3022

Re: 4264 vs. 2164 RAM chips

Hi Gyro Gearloose, I was doing some research online on RAM chip identifying numbers and Google brought this thread up. Hmmm, forgive my intrusion upon this learned discussion, but I think you can just pop in a 41256 chip in lieu of a 4164 and it should work as a 64k chip. The C64 will simply never a...
by banman
Fri Aug 07, 2020 11:07 am
Forum: Hardware
Topic: The elusive KU boards.
Replies: 6
Views: 1858

Re: The elusive KU boards.

Hi eslapion, I have used an original genuine ST M27C512-90B6 PLA EPROM based substitute on both KU style boards and have not detected any glitches with an oscilloscope on !ROML or !ROMH pins of the PLA as yet. Apologies, I have misquoted the ST M27C512-90B6 PLA EPROM. I in fact have these pair of or...
by banman
Fri Aug 07, 2020 5:33 am
Forum: Hardware
Topic: which chips fail the most on the 64
Replies: 8
Views: 1013

Re: which chips fail the most on the 64

Something happened to me recently. It's not exactly a chip which fails on the C64. However I feel it is something to watch for. I have been doing quite a bit of testing of some chips on the C64 mainboard. My best practice testing procedures can be sketchy at the best of times. :lol: I couldn't get t...
by banman
Fri Aug 07, 2020 4:46 am
Forum: Hardware
Topic: The elusive KU boards.
Replies: 6
Views: 1858

Re: The elusive KU boards.

Hi eslapion, A few years ago, Thomas 'Skoe' Giesel tested a bunch of different original PLAs as well as a few PLA substitutes. This include my earlier generation of PLA substitutes based on genhine ST M27C512-90B6 which I call PLAkate. Skoe confirmed my claims genuine ST PROMs don't cause bus conten...
by banman
Thu Jul 16, 2020 11:30 pm
Forum: Hardware
Topic: which chips fail the most on the 64
Replies: 8
Views: 1013

Re: which chips fail the most on the 64

That's nothing, here is a chip made in 1922. https://www.ebay.com/itm/1PCS-IC-MOS-DIP-40-MOS8502-MPS8502-CSG8502-8502/362991698682?_trkparms=aid%3D1110001%26algo%3DSPLICE.SIM%26ao%3D1%26asc%3D225085%26meid%3Df1b4013d46ad46eb8bdb2af9e62b9f95%26pid%3D100005%26rk%3D5%26rkt%3D12%26mehot%3Dpf%26sd%3D164...
by banman
Thu Jul 16, 2020 11:24 pm
Forum: Hardware
Topic: Adrian's RF modulator video cleanup
Replies: 9
Views: 1109

Re: Adrian's RF modulator video cleanup

Hi rmzalbar, I was looking for something about how to troubleshoot the C64's rf modulator. I came across this.... https://youtu.be/7_VjwySbnzQ I have one Longboard breadbin C64 that has symptoms very similar to what Adrian has. I get sound from the 8 pin video connector and nothing from the RF modul...