Search found 61 matches

by LoneWolf33
Sat Sep 28, 2019 2:42 am
Forum: Commodore Discussion
Topic: The C65 #1 at the Amiwest Show 2017
Replies: 4
Views: 2421

Re: The C65 #1 at the Amiwest Show 2017

Thanks for the feedback !

I think there's very limited info available on the net about these expansion boards.
As I heard there are multiple revisions (maybe 3?) are exists in very limited numbers,
and they might not interchangeable freely between the different C65 mainboard revisions.
by LoneWolf33
Thu Sep 26, 2019 12:55 am
Forum: Commodore Discussion
Topic: PET Cassette port issue
Replies: 1
Views: 264

Re: PET Cassette port issue

Hi, The cassette ports are handled by different chips, that could explain the symptoms. The read line of cassette port#1 (marked as "J3" on the mainboard) is connected directly (without any level conversion) to the 6522 VIA IC, while the read line of cassette port#2 (marked as "J6") is wired to the ...
by LoneWolf33
Wed Apr 10, 2019 5:16 am
Forum: Commodore Discussion
Topic: Commodore 128, 80 column mode displayed on modern monitors
Replies: 2
Views: 1025

Re: Commodore 128, 80 column mode displayed on modern monitors

Hello, I've faced the similar problem a few months back. I've bought an RGBI (CGA) to RGB adapter from gglabs ( https://gglabs.us/node/2022 ), and created a SCART adapter cable to it, so it can be used with any TV set that have RGB capable SCART input. It works nice, but doesn't looks too fancy, sin...
by LoneWolf33
Mon Jan 14, 2019 2:10 am
Forum: Commodore Discussion
Topic: What do I plug a Commodore 64 into?
Replies: 3
Views: 1279

Re: What do I plug a Commodore 64 into?

At the time C64 was designed to be used with TVs or video monitors. There are two basic ways to connect the 64 to a TV: - Baseband A/V: this requires an adapter cable between the C64's video connector and the TV / video monitor in this case the TV should have RCA or SCART A/V input(s), the adapter c...
by LoneWolf33
Fri Dec 14, 2018 3:31 am
Forum: Commodore Discussion
Topic: Commodore PET 4016 Blowing Fuses.
Replies: 1
Views: 1157

Re: Commodore PET 4016 Blowing Fuses.

Hi, This can happen when the contacts of the power switch are welded together due to the overload, so the circuit remains complete towards the primary winding of the power transformer, despite the OFF position of the switch. I'd recommend to find the root cause first, because just replacing the fuse...
by LoneWolf33
Tue Nov 27, 2018 11:37 pm
Forum: Commodore Discussion
Topic: PET 2001N 16k upgrade ram
Replies: 4
Views: 1366

Re: PET 2001N 16k upgrade ram

I've found an image at zimmers.net which describes the jumper/DIP switch configurations: http://www.zimmers.net/anonftp/pub/cbm/schematics/computers/pet/2001N/320351-6.gif I guess this fits for your PET2001N motherboard. If so, then it seems only SH2 DIP bank settings are need to be changed in order...
by LoneWolf33
Tue Nov 27, 2018 4:45 am
Forum: Commodore Discussion
Topic: PET 2001N 16k upgrade ram
Replies: 4
Views: 1366

Re: PET 2001N 16k upgrade ram

Hi,

They're pin compatible, the TMM416D-4 has a bit slower access time: 250ns vs 200ns.
IMHO the spare ICs are suitable for the RAM upgrade.
by LoneWolf33
Fri Oct 05, 2018 3:03 am
Forum: Commodore Discussion
Topic: Commodore 1902A "Vertical Collapse" problem
Replies: 4
Views: 1469

Re: Commodore 1902A "Vertical Collapse" problem

Hello, I think they're still available, or at least the IC402 (TDA2595) which was also used in TVs as well. You can make sure by checking the exact IC types on the packages and google them. IC302 is mounted adjacent to a heatsink at the centerline of main PCB, near to the rear edge of the panel, bel...
by LoneWolf33
Sun Sep 23, 2018 2:53 am
Forum: Commodore Discussion
Topic: Commodore 1902A "Vertical Collapse" problem
Replies: 4
Views: 1469

Re: Commodore 1902A "Vertical Collapse" problem

Hello, It seems the problem is probably related to one or more of the following: - missing vertical sync pulse generation, or the pulses are not reaching the vertical driver stage - vertical driver stage - missing 26 Volt power supply of the vertical driver stage - vertical deflection coil on the CR...
by LoneWolf33
Sat Sep 08, 2018 3:30 pm
Forum: Commodore Discussion
Topic: Commodore CBM 8032: Help with repair
Replies: 1
Views: 1055

Re: Commodore CBM 8032: Help with repair

Well, the picture shows only a normal startup screen :wink:
At least for me this is the only picture that appears in your post.

There might be a problem with the CRTC chip memory access.
by LoneWolf33
Fri Mar 30, 2018 12:37 am
Forum: Commodore Discussion
Topic: Pet2001 load problem
Replies: 1
Views: 1401

Re: Pet2001 load problem

Hello, The most probably cause is weak signal from the R/W head due to the following: - wrong azimuth setting of the R/W head - the air gap of the Read core is clogged (by microscopic tape fragments) - too large air gap in the Read core of the head (mechanical wear, resulting drop in the frequency r...
by LoneWolf33
Fri Jan 12, 2018 6:33 am
Forum: Commodore Discussion
Topic: The C65 #1 at the Amiwest Show 2017
Replies: 4
Views: 2421

Re: The C65 #1 at the Amiwest Show 2017

I guess the RAM expansion board captured by Robert is even rarer than the C65 itself :)

Does someone know how many of these expansion boards are still exist ?
by LoneWolf33
Wed Sep 20, 2017 11:59 pm
Forum: Commodore Discussion
Topic: What error to expect of LOAD is mistyped as LAOD
Replies: 1
Views: 1834

Re: What error to expect of LOAD is mistyped as LAOD

You will get a "?syntax error" message on the screen.
by LoneWolf33
Mon Sep 04, 2017 10:46 am
Forum: Commodore Discussion
Topic: PET 8096-SK boots to machine code monitor
Replies: 13
Views: 5932

Re: PET 8096-SK boots to machine code monitor

If it's not already done, I'd recommend to check all power supply voltages on the mainboard (+5V, +12V, -5V). The 4116 RAM chips are extremely sensitive to the missing negative supply, it destroys the chip in no time. Dead filter capacitors can cause fluctuating or too low voltage, causing abnormal ...
by LoneWolf33
Mon Sep 04, 2017 9:51 am
Forum: Commodore Discussion
Topic: PET 8096-SK boots to machine code monitor
Replies: 13
Views: 5932

Re: PET 8096-SK boots to machine code monitor

As far as I can tell there's a subroutine call at address $E5B7 during boot. The chirp routine itself is located at $E6A7, generates only one chirp, so it's called multiple times during a successful boot. Once Basic was started normally you can call the chirping routine manually by typing the sys590...