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 Post subject: PVM 20L2 - Help!?
PostPosted: Thu Aug 09, 2018 3:30 pm 



Joined: 08 Jul 2018
Posts: 6
I bought a PVM the other day, which was a source of great excitement. The testing of it went well at the house of the person I was buying it from - multiple systems tested and everything looked great. I got the thing home and waited a couple of days for my BNC cables to arrive. Once they arrived I hooked everything up and was greeted with the awful sight of the screen in this link:


https://www.reddit.com/r/crtgaming/comm ... ck_smears/

I'm puzzled as to how this has happened over the course of a few days and moving the monitor from one place to another. I've opened the PVM up and tried adjusting the "screen" pot but this just made things either overly bright, or a shade of red - both still exhibited the streaks however (I've put it back to where it was).

I'm hoping somebody among you folks can be be of some assistance, because I've got no ideas left. Was I screwed by the guy I bought it off? Could it be a bad cable?

Help!

(cheers)


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 Post subject: Re: PVM 20L2 - Help!?
PostPosted: Thu Aug 09, 2018 4:15 pm 


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Joined: 17 Apr 2008
Posts: 1529
I've seen that caused by bad cables, try some other cables.


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 Post subject: Re: PVM 20L2 - Help!?
PostPosted: Sat Aug 11, 2018 4:13 pm 



Joined: 08 Jul 2018
Posts: 6
Well, I tried a different power cable and it didn't make any difference. It's not caused by bnc cables as this effect can be seen even when theres nothing else connected to the back of the monitor.

Looks like I got swindled by the seller. Wonderful. That's me done with pvm's.


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 Post subject: Re: PVM 20L2 - Help!?
PostPosted: Sat Aug 11, 2018 8:02 pm 


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Joined: 17 Apr 2008
Posts: 1529
You're dealing with extinct technology man, you're gonna have some road bumps here and there.


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 Post subject: Re: PVM 20L2 - Help!?
PostPosted: Wed Aug 15, 2018 5:19 pm 



Joined: 08 Jul 2018
Posts: 6
I tried using some 75ohm terminators on the outs on the back of the monitor but no difference. I guess I can either try recapping it (and possibly making things worse, or killing myself on the anode) or dumping the thing. The seller saw me coming lol.


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 Post subject: Re: PVM 20L2 - Help!?
PostPosted: Wed Aug 15, 2018 5:25 pm 


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Joined: 08 Jan 2016
Posts: 435
Location: San Jose, CA
You don't need 75-ohm terminators on a PVM. Changing the power cable is pointless. That can't be your cable because your cable isn't responsible for the 'RGB' overlay text.

There is no need to be so dramatic. This is an old monitor being used for video games.

Turn down the "bright" knob (which controls overall bias) for the time being to bring your black level to an actually black level. The streaks will not be visible on the darkened screen. Try with an actual video source and take a clear picture of what is wrong.

You may have simply not noticed these issues when you bought it. Declaring it a scam is going overboard. In all likelihood, this is an old monitor, and needing to recap the signal section is nothing out of the ordinary. If your response is to take it to the dump if it needs such minor work, then I suggest you find a mindless hobby instead of this one. At the very least, give it to somebody who is willing to learn a little and work on something.
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 Post subject: Re: PVM 20L2 - Help!?
PostPosted: Wed Aug 15, 2018 5:37 pm 



Joined: 08 Jul 2018
Posts: 6
I guess I'm just annoyed in that I spent a fair bit on it with the seller saying it had recently been refurbished and it all looking hunky dory, thinking I wouldn't have to deal with problems like this.

Anyway, I know pvms are supposed to have terminators built in, I just read somewhere that the automatic terminators on pvms can fail and that others had remedied this issue with the 75ohm attachments. Obviously didn't work for me though. Just thought I'd try it to avoid having to go inside the thing where I've got no clue what I'm doing. I've done some amateur soldering before but going at something like this feels a bit beyond me.

As for the age of the monitor, the back says 2004 - positively spritely for one of these monitors I thought.

I'll bung it on ebay and see if I can at least recoup at least some of my losses.


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 Post subject: Re: PVM 20L2 - Help!?
PostPosted: Wed Aug 15, 2018 7:05 pm 



Joined: 19 Oct 2013
Posts: 409
Location: Riverside, CA
https://www.manualslib.com/manual/12820 ... 20PVM-20L2

Now you can find RV709.

I second MJM's sentiment, but maybe not his abrasiveness. Put some effort in, learn a thing or two, enjoy the hobby for what it is: using older technology that often requires repairs. Learning how to fix things and actually fixing them is half the fun of it.

Worst case, find some stuff to practice on, get your soldering up to snuff (it's only through-hole components), discharge it, then go about snipping those capacitor legs with some snips, write down each location, and make an order. Then heat up the holes and pull the legs out, and prep them for the new caps. Put in new caps, snip the extra length of leg.

While it's apart take a bit of time and examine it with a magnifying glass and see if you can find any obvious cold solder joints.

A 20L2 isn't an expensive monitor, so unless you actually got swindled (on the price, because you said yourself it worked fine at his place), you can't be out that much. Nor is it a difficult one to work on since it's so heavily documented. The majority of CRTs don't have publicly available service manuals at all, you've landed a monitor that has one readily available, and for free.


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