Denial

I have about 5 vics, 2x 2-pin and 3x CR models

Of the CR models none are 100% working

Vic 1) [The one I use] seems to have a flickery screen when I connect the Wifi Modem to the user-port (works fine on C64 and other Vic). In all other respects it's is fine.

Vic 2) I used to use this one, but one day it refused to power up having just a black flickery screen. (I was advised on here that it may have been caused by a failing PSU so now I am using one I got from Ray Carlson).

Vic 3) Powers up and screen displays fine (no flickering with Wi-Modem) but all the characters display as the '@' sign.

What I would like to know is if any of these could be repaired by replacing/copmbining parts from others and what chips would be suggested to swap or reseat etc

Thanks!

beamrider wrote:I have about 5 vics, 2x 2-pin and 3x CR models

Of the CR models none are 100% working

Vic 1) [The one I use] seems to have a flickery screen when I connect the Wifi Modem to the user-port (works fine on C64 and other Vic). In all other respects it's is fine.

Vic 2) I used to use this one, but one day it refused to power up having just a black flickery screen. (I was advised on here that it may have been caused by a failing PSU so now I am using one I got from Ray Carlson).

Vic 3) Powers up and screen displays fine (no flickering with Wi-Modem) but all the characters display as the '@' sign.

What I would like to know is if any of these could be repaired by replacing/copmbining parts from others and what chips would be suggested to swap or reseat etc

Thanks!

That's difficult to answer if you don't say what's socketed and what's not on your various boards.

Are you using Ray Carlsen's PSU with your VIC 1) ?

I suspect the kernal of your VIC 3) is bust. It might be worth it to try using VIC 1)'s ICs on it.

Concerning the VIC 2), if a failing PSU causes problems then it will likely damage multiple ICs on the board so just replacing the PSU obviously cannot fix the problem. Send the mainboard to Ray Carlsen.

thanks, I haven't opened them up so not sure yet.

Will give your suggestions a try..

I don't want to mess with my one working Vic (1), so I might try and move the Kernal roms from 2 -> 3 assuming they haven't been trashed. The flicker with WiModem has been reported by others. Some machines seem susceptible to it while others aren't...

As mentioned I have a couple of two-pin Vics but they are yellowed and grubby. Maybe I can swap=out the main boards from one of those to case of (2).

Oh and yes, I only use the new PSU now for any 5-pin machines..

Since you mention 2-pin Vic-20 I am assuming you have the American NTSC versions.

You can use the IC's of a 2-pin Vic-20 into a CR one, if that is what you are asking. Switching the whole board is no problem at all since the cases are identical.

The 6560 (usually enclosed in a metal box, unless you have a Vic-20 with a FCC waiver on it) is swappable between systems, but as eslapion points out, a failing psu can damage other components as well. That is a big IF, since you only mention that someone suggested this and not that you have confirmed that the psu was the cause of the problem.

If you have ICs that are in sockets (most are not), then they are easy to take out with a special tool. You can get one out without this tool as well (I often use a small flat screwdriver), but one has to be VERY careful, and for the 6560 it is almost impossible since its on the bottom of a narrow box. You also risk zapping the ICs with static electricity if you don't wear a grounded wrist strap.

ICs that are not socketed needs to be desoldered with a soldering iron and solder pump. You should train on something else if you haven't done this before and buy some sockets to solder in once you have desoldered an IC.

Thanks..., by 2-pin I meant the ones with the internal transformer from 9VAC and two pin connector. Still UK models.

I probably wouldn't go to the trouble of de-soldering, so unless both are socketed I'll give it a miss. Will have a look and if so, order the extractor from ebay.

Cheers!

Kakemoms wrote:Since you mention 2-pin Vic-20 I am assuming you have the American NTSC versions.

Why exactly would you assume something like that ? My first PAL VIC-20 was the 2-pin PSU kind.

The one I have now is a VIC-20cr so clearly both the 2-pin and the CR exist in both PAL and NTSC flavors.

beamrider wrote:Thanks..., by 2-pin I meant the ones with the internal transformer from 9VAC and two pin connector. Still UK models.

I probably wouldn't go to the trouble of de-soldering, so unless both are socketed I'll give it a miss. Will have a look and if so, order the extractor from ebay.

Cheers!

Ok so if you only have UK models they will have the mos 6561 and not the 6560. As long as you dont mix them you are ok.

If you are in the UK it would be expensive to use Ray Carlsen for the repairs. Try finding some local solder guy at a hackaton or alike to put in sockets.

Had a bad Vic day yesterday and the situation gets more confusing. ...sorry for the rambling thoughts and queries in advance

Vic (1) stopped working suddenly whilst play Arknoid, crashing then going to a black screen...I am wondering if using the WiModem from Cbmstuff.com could be damaging to my Vics as it displays a slight flickering and false joystick inputs seem to affect the megacart menu at bootup which doesn't seem right. Also, the mega-cart seems to have been affected as I had to reinstall SJLOAD. I was even begining to suspect Ray's power supply at one stage.

On the plus side, the VIC that I thought was broken (2) - flickering black screen at power-up has started working again after several attempts at powering up. Seems to be worse the longer it's been left switched off. I am wondering if there could be a capacitor that needs replacing?

So now I am back to Vic (2) but this seems to have louder and more distorted sounds - any way this can be attenuated internally to clean it up a bit?

VIC (2) sounds like a dying capacitor in the reset circuit. I have one that does not reset on power up but it works great if I use the reset button on my 32K RAM expander (Dorktronic.)

Thanks, I'll try that next time it presents a black screen.

Anyone know the location of the likely capacitor?

Just discovered this which seems to contain lots of useful info....

http://personalpages.tds.net/~rcarlsen/ ... /vic20.txt

Yes the doc you linked to is very useful indeed!

I doubt it's the Wimodem. I've used it on 3 different Vics without any issue. One time I left one on for 24 hours with the Wimodem and no problems. On the other hand, all of my VICs are fully refurbished and heat sinked. I also use modern safe power supplies. I think yours just have age-related issues and need service and the power supplies should be properly tested for voltage and ripple. Half of my 15 Vic-20s didn't work when I bought them and the other half had various other issues. They all needed service.

NOTE: 6560 and 6561 are NOT swappable:
they are feeded with different xtal clock frequency that is in relationship with the colour portant frequency,
so the relationship between xtal input clock and generated system clock are different into two chips (and probabilly 6561 can't run up at xtal clock highter frequency of 6560...)

Kakemoms wrote:If you are in the UK it would be expensive to use Ray Carlsen for the repairs.

Well, half as expensive... i.e., I will be in the UK starting in September, and I can bring back a broken machine for Ray to repair.

Space in the suitcase,
Robert Bernardo
June 10-11 Pacific Commodore Expo NW -
http://www.portcommodore.com/pacommex
July 29-30 Commodore Vegas Expo v13 -
http://www.portcommodore.com/commvex

P.S. I don't combine VIC-20's to make working VIC's, but I do combine Plus/4's to make working ones.