MODEL IIIA monitor problems
Posted 14 April 2006 - 11:08 PM
I just bought a IIIA from Derrick Whitehouse a couple of weeks ago. I first went and checked it out and everything looked OK with it. Derrick powered it on and fed a signal through it and everything looked ok. I came back a month later and bought it from derrick. I didn't really get to play with it because I didn't have batteries and my vest needed work. I finally got it turned on and the vertical hold was out of control. I didn't see an external adjustment and just assumed the monitor was damaged. Joe Broderick told me about the adjustment inside the base and that worked great. Now when i power it on, the image looks good and is sharp but immediately starts a slow transition into a very soft looking image. Takes about a minute or two until the entire screen is out of focus. It usually starts from right to left. It resets itself whenever I fully power down...Standby doesn't change anything. I was hoping I could avoid sending it in for a repair by making another adjustment if it even exhists. I was wondering if anybody has had the same problem before and might be able to share what needs to be done to fix this problem. I would really appreciate any info you guys have.
Posted 15 April 2006 - 03:23 AM
Now when i power it on, the image looks good and is sharp but immediately starts a slow transition into a very soft looking image. Takes about a minute or two until the entire screen is out of focus. It usually starts from right to left. It resets itself whenever I fully power down...Standby doesn't change anything.
IIRC your voltage tripler is dying. Talk to Terry West (Search in the archives for his phone number) He might be able to help you out. If not start thinking about either a TB-6 or Pro Monitor or a LCD Conversion
Posted 15 April 2006 - 04:34 AM
The problem is, if the monitor is a goner... you basically can trash everything below the Gimbal as the monitor is only a part of the set up the rest is in the Electronics housing... Then basiclly you are starting from scratch.
If nothing else, there is a British based company that specializes in salvaging 3A's and giving them a couple of years more...
But start with calling Terry... he has resurrected a couple of sleds in the past.
Posted 15 April 2006 - 03:52 PM
And it is true- the "West Docking Bracket" was named for him. I don't think he invented it, though he might have. Terry ?
Posted 15 April 2006 - 06:40 PM
Do you remember the IIIA I had at your workshop? It had the same problem. Eric and Erwin are right, your trippler is bad and when I resereched it, there weren't a lot of those around. There is a little red/orange knob connected to the board at the base of the tube. You can adjust the monitor's picture with that knob. It's only a quick fix. It seemed to work best on mine when I would let it get completely out of focus. Then I would adjust it and it would stay good for a while but eventually drift out. But like what has been said to you in these other posts, start thinking about a new monitor.
Posted 16 April 2006 - 12:38 AM
I started with a IIIa too, had similar problems, opened the housing and in the dark I looked where the problem was: if it is in the tripler, you might see sparks and arcs under the silicone.
There might be two things you can try then: find the High Voltage condensors that are normally blowing out and replace the affected parts, (dig out the affected components from the silicone)
or completely remove the HV-cascade and replace for a solid state one from a color television, they are still out there in repair shops or electronic dumps.
I used to make a whole manual about this repair once, it might be still on one of the old forums, though I am not sure about it.
I cannot find it here anymore, but a good television-repair man might be able to do this (and has the measuring tools too)
I remember in my set I could mount the HV unit (smaller than a pack of cigarettes) IN the monitor housing, rewiring some lines from the main electronics so the HV (18.000 volts)is not anymore through one of those metal umbilical cords, only the "lower 6000 volts" or such. It needed a resistor somewhere to limit the current through the rectifier tube, but other than that is was not much of a job.
The Solid State Cascade was about 4 dollars if I remember correctly.....
Let us know what happened if you give this a try! There are more IIIa's out there and dying....
Posted 18 April 2006 - 10:59 AM
sorry to it took so long to report back. I'm just rapping up here on the show I work out and its just getting a little hectic. I did call Terry West and he was very helpful. I'm going to bring my rig to him and he will take a look at it. He did say that if it is the voltage tripler, then it may be difficult to repair or replace? I might not be quoting him accurately! He did mention that I could gut the base and attach another monitor which is something I wanted to do in the long run....just not now. I was really hoping to upgrade my springs and get a bartech first. Oh well...it is what it is. Thanks so much for all the input Erwin, Eric, Peter, Jay, and Rob. I really appreciate you guys taking the time to help me out. I'll post again with the results of what happened. thanks