Recent content by Wreck

Thanks, Hugo, for your very valuable input. I didn't have time yet to check further, however my 22pf capacitors arrived. At the next suitable occasion I will continue with the troubleshooting. What confuses me mildly are the two resistors R7/R8 in the oscillator loop which are, according the...

It is definitely helpful to have a large cupboard with plenty of spares, but probably more important to have an understanding wife. Going to get some 22pF Capacitors tomorrow...unfortunately they don't look original.

OK So I traced the problem all the way back to the 16MHZ crystal Y1. for some reason or the other it is not producing any signal. I suspect C44 being faulty, but need to confirm once I have a bit more time.

After fixing the reset circuit, havin a nice and stable platform, I thought I will hook up a cassette tape and try to load a test program from tape to see how things are with loading stuff from external sources. Soon after the tape was searching for the program, the picture started to wobble...

Hi Dave, I will clean the board again to make sure no gunk remained from previous repairs; somebody soldered new 2114 sockets in, and even I am quite a layman, can say the job doesnt look great (no impact on function). I will try and replace the capacitor, have got tons of ceramic capacitors...

So now with C68 removed, the CBM runs fine (needs a manual reset after power on). Starting from the 555 I now have the following; A2 PIN1 LO PIN2 HI PIN3 LO PIN4 HI PIN5 HI PIN6 HI PIN7 LO PIN8 HI The inverter at A3 works at it should; PIN1 LO PIN2 HI The buffer at A10 has both PINs 13 and 12...

I desoldered the ceramic capacitor at C68 today, to have it tested on the bench, and thought "lets see what happens if I turn the machine on without this thing installed". To my surprise the CBM works normally (it needs a push on the external reset button), PIN40 on the 6502 is HI and there is...

Hello, My trustworthy 3032 developed several hiccups over the past months. Suddenly it wouldn't start, only with the help of the PET ROM/RAM board it would, but the Commodore text would be "wobbly" (with interference). The system has the original white sockets installed. Applying a bit of...

I was able to trace the machine back to his original owner; a certain Boris Eelzebub, it appears. I put in the replacement 901466-02 today, no difference when turning on. Checked all sockets again, still have SYNC LO on the 6502. Whenever I type in any LOAD command and execute, the center LED...

I was able to burn the 2732 from $C00 to $FFF, but no difference (actually it is worse now, as the drive motors won´t spin up at all). Also, 6502 PIN7(SYNC) is LO again...so back to square one. I will be getting a spare 901466-02 over the next few days, will see if this makes any difference. In...

Thanks Dave! I will try this afternoon. I am using an old GalepIII with software running under WIN98. Joe

Just out of curiosity; in a German service manual of the CBM the first troubleshooting step is to check the multiplexers (UD3/UE3/UF3) with the aid of a NOP tester. I just did and found UD3 PIN7(output) dead (no activity except 5V). But I guess I am jumping around, I will start with the RRIOT...

I am relieved regarding the capacitors. Regarding the 2732, I only programmed it once (so probably a mistake on my side), so I will try a 27128 (haven´t got any at the moment I think, so need to source). In the meantime I will try and figure out how to burn the 2732 four times; I haven´t used...

So to start with, I am building a simple NOP tester as follows (6502) Pin 33, 31, 29 to 21 (GND) and Pin 32, 30, 28, 27, 26 to 8 (Vcc) This will keep me busy for a while :-)

I have, essentially, used the following adapter, made by PCBWay. There is a difference in the (decoupling) capacitors used; Ruud Baltissen uses 220n whereas in the PCB Way description it says 100nf. I used the 901466-02.bin file from Zimmers. It is a 1kb file...