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commodore 4016-n with extreme water damage

Ideally, you'd try to snag ones where the CRT is electrically similar to a CBM.
The lifespan depends primarily on how quickly the cathode deteriorates. In the case of old or cheapo CRT's, this is around 10k hrs to 20 k hrs to reach 50% brightness.
Newer technology CRT, using dispenser cathodes, figure >50k hrs. Phosphor deterioration becomes a factor during aging as well, but more with color CRT's.
patscc
 
so is that 14 to 28 years with 24/7 use with an old or cheapo crt, thats not bad if I found a low used one, I dont know where I would get a good modern 12 inch monochrome crt?
so I will lookout for some 12inch black and white tvs
with a valve/tube I can test emission agenst a data sheet to see how worn it is, can the same be done with a CRT?
 
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how do I find if the CRT is electrically similar to a CBM? I know about valves, and basic eletronics and how a crt works rufly, but I have never done more than clean a crt to fix it!
where would I get data sheets on old CRTs? probably from 1970 to 1980s tvs
its a shame their are not any tv repair shops around me as I could probably get it all done there
 
I think some CRT testers, like the better Sencore's, let you do that, but I won't swear to it. It's been a long time since those days...
Portable B/W sets at fleamarkets and the like ?
Can you post the part number you have on the CBM CRT, and I'll see if I can find some matches in some cross-reference books. Assuming I can find the cross-reference books. It's been a long time since those days...
patscc
 
Screen burn's the usual problem, probably more of an issue than low emission.

As I've mentioned a few times I think I may have a few brand new suitable CRTs; I'll have to check, but probably wouldn't be feasible to ship anyway.
 
I have a friend that runs a sort of junk shop, that may be able to snag some as they are not worth enething, and there are 2 dumps by me that have loads of tvs for recycling but they are keped outside stacked up high and get brocan? and they are not suppose to let you recical any item anymore, new recycling regs!!! but maby?
the old water damaged crt had a part lable but it fell off! when I cleaned it, but I saved it.
I will have to see what crt testers cost, and see if my CRT rejuvenater can test crts? I remember it has an analog meter on it?
 
I have only ever seen screen burn on some very old green small vga and orange cga monitors I had, can tvs get screen burn?
the good commodore's crt looks ok at the moment, but I have not tested the water damaged one, the pins were croded and the black coating came off! but I fixed that.

I would only need a matching crt for the good commodore, the water damaged one will always be a Frankenstein lol I live in the uk so shipping would probably cost a lot

MikeS said:
Screen burn's the usual problem, probably more of an issue than low emission.

As I've mentioned a few times I think I may have a few brand new suitable CRTs; I'll have to check, but probably wouldn't be feasible to ship anyway.
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I had a look on ebay a Sencore CRT tester £140 50% of that is shipping! all the other crt testers/Rejuvenators are cheap, but also the us? so about £40 shipping min, maybe the crt Rejuvenator I have can test too? I will have to see?
 
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Why do you think you need a tester/rejuvenator? Have you checked the various signals and voltages from the main board and in the monitor? I don't think I've ever seen a monitor CRT that needed replacement unless it had screen burn, the filament was burned out, or there was arcing or a short between electrodes.
 
MikeS said:
Why do you think you need a tester/rejuvenator? Have you checked the various signals and voltages from the main board and in the monitor? I don't think I've ever seen a monitor CRT that needed replacement unless it had screen burn, the filament was burned out, or there was arcing or a short between electrodes.
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I was just thinking it would be useful to know how far the CRTs used in my old commodors are threw there life, and especially any replacement 12 inch tvs I collect for them. I dont want to store a CRT that's nely worn out!

as the Frankenstein commodore will be on all the time working the CRT will ware the out much faster.
I have read out about rejuvenators for radio tubes and the CRT one works the same way, and is only for a last chance tube as it sacrifices run time for higher emission!

dose any one still use commodore pet/cbm 24/7?
 
screen saver and screen burn

screen saver and screen burn

dave_m said:
This would not be a good idea as old monochrome CRTs are susceptible to screen burn-in if left with static images or text. The PET does not support a screen saver type function.
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I could rig a circuit so if I haven't used the keyboard in say 10m then it dims the crt, that would help, and the program it will be runing all the time will have constly changing data, and I could wright a screen saver in, maby put an extra carecter eprom in and have falling matrix code?
 
MikeS said:
I don't think your PET will be quite fast enough for that sort of thing...
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maybe, but it has PETSCII that would look much better making graphics but I would have to make my 4016 a dual 4032/8032 and use it as a 8032 for something like this http://www.youtube.com/watch?v=kWK0lKKaNKE but with better PETSCII but low frame rate, I will keep an eye on the petpix from bitfixer

the "graphics" controller cant put that enough characters on the screen, maybe with a commodore high resolution graphics board? look at "Graphics Display Examples" http://www.6502.org/users/sjgray/computer/hsg/index.html

how many pages of PETSCII can be displayed per minute? probably much faster in machine code
 
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I have got the commodore 8032 working it was another bad 2114 1k video ram chip, I have gone threw mone than 5 chip! I checked and the supply to the 2114 is 4.98v so it is fine? the orignal 2114's whee MOS Technology 2114's and the first set of replasements where nos from the 1970s but I now have some new 55ns 2114's, will all the 30~ year old 2114's die on me?

before
IMG_20120924_191255.jpg

after
IMG_20120924_193752.jpg

now I can start swaping chips with the sick 4016
 
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