UB9 M53202P

[Tormentor]

Sadly upon booting up for the first time in over 5 years, I have squirrelly diagonal color stripes going crazy across the screen. You can't really make out the screen at all, just the raging colors.




Based on the troublehsooting guide it looks like it could be UB9?

I don't see this part currently for sale anywhere. If I wanted to replace it to see if it was the problem, is this part the same one?

http://www.weisd.com/test/GenericParts_ ... d1=M53202P

Thanks for any guidance or suggestions.

UB9 7402 (M53202P) OSC MASTER CLOCK OSC
White screen... no RF interference in AM radio (see text). Partial failure
can produce missing color or incorrect colors, slight or severe tearing of
picture or diagonal lines, sounds play at incorrect pitch. Symptoms may only
appear after warmup.

[eslapion]

I don't think it's UB9 at all.

I can see in the video garbage that the CPU is running. You can make out the familiar "**** CBM BASIC V2 ****"

It's not possible to know with your text and photo if this is a TV set connected through a modulator or a monitor with a direct composite connection.

I strongly suspect a pot located near the VIC-I needs readjustment or if you used the modulator, there may be a problem with it.

Your profile doesn't indicate what country your in so it's not possible to know if your VIC-20 is a PAL or NTSC model.

[Tormentor]

Thanks!

U.S. Vic here. I'm connected to the TV with an RF Modulator 15-1268A. VHF connected to coax input on the TV..the TV doesn't have antenna posts, just coax and line inputs.

So you think I might need to try another modulator (maybe this one is bad)?

[eslapion]

So you think I might need to try another modulator (maybe this one is bad)?

I think the most likely candidate is the potentiometer adjustment near the 6560 chip.

However, as I found out myself recently, only relying on what you see on screen to adjust it may not be enough. Usually, you need an oscilloscope to do it right.

Added edit:
TLR is correct, the photo you posted is the 300/75 Ohms switch - not the modulator.

[tlr]

U.S. Vic here. I'm connected to the TV with an RF Modulator 15-1268A. VHF connected to coax input on the TV..the TV doesn't have antenna posts, just coax and line inputs.

So you think I might need to try another modulator (maybe this one is bad)?

Maybe I'm missing something but that doesn't look like an RF modulator to me. Isn't it just a switch? If so where did you connect it?

[mrr19121970]

I know it's not relevant, but you can get the UB9 on eBay, no issue. This is what I bought.

[Tormentor]

Doh! Sorry for the stumbling and bumbling on posting the switch. Yes, I have the original 5 pin DIN to the original little black modulator box, and the rca style plug to the switch.

I see from wiki that there could be potential corrosion on that RF box, so I need to check for this weekend. All my Commodore stuff has been in climate controlled conditions (in the house proper, no attics or garages) since the 80s, but I guess the age of this stuff means anything is possible.

Wondering if I should just skip the RF. This cable claims to be the right one, and looks like it. Would be nice to have composite out to be able to use more TVs than that tiny 9 inch last tube one I own. eBay AV Cable

I searched the forums here, and didn't see anything current, but if someone here in the community sells cables, reply here if it's allowed, or PM me if site rules prohibit it, because I'd rather give money to Denial enthusiasts for Vic 20 items than just some eBay listing.

Thanks again all!

[eslapion]

I know it's not relevant, but you can get the UB9 on eBay, no issue. This is what I bought.

You can probably use a 74LS02 on a PAL VIC-20 because these use a crystal of less than 10MHz. However, the OP being in the U.S., his NTSC VIC-20 uses a crystal of 14.31818MHz and this usually requires the use of a faster chip, hence a 7402 or 74S02 was recommended.

Nowadays you can probably use a 74ACT02 but I think they are only availabel in surface mount packaging.

[eslapion]

Wondering if I should just skip the RF. This cable claims to be the right one, and looks like it. Would be nice to have composite out to be able to use more TVs than that tiny 9 inch last tube one I own. eBay AV Cable

That should do the trick.

All you need is a TV with a "video-in" connector but some flat panel TV don't like the "not quite standard" video signal from VIC-20s, Commodore 64 and various 80s game consoles.

[Tormentor]

That should do the trick.

All you need is a TV with a "video-in" connector but some flat panel TV don't like the "not quite standard" video signal from VIC-20s, Commodore 64 and various 80s game consoles.

Thanks, I pulled the trigger on an ebay cable, we'll see what shows up and if it works