Star Trek G08 issues

Zinfer

Well-known member
Joined
Apr 19, 2008
Messages
4,497
Reaction score
32
Location
Lima, Ohio
I've tried asking in Monitors help channel but no responses.
I'm pretty sure there's some G08 pro's out there. But anyhow the gist of my request is that I'm getting the screen below.
Has anyone come across this before, where the left half is not there and the screen is collapsed?
Pretty much come to the self-conclusion it'd be a good idea to replace all the surface mount deflection board transistors as I don't know the history other than alot of burnt resistors and 2n3716 Bob Roberts G08 Rebuild kits.
But before I spend the $80.00 on transistors(NTE171, NTE240), wanted to see if anyone else had seen or come across this. www.zinfer.com/startrek.htm for full details.
IMG_0706.jpg
 
Last edited:
It has been a while but I believe I ran across something similar about a year ago. I replaced a board mounted deflection circuit transistor and fixed it. For component information check out biltronix.com. He has some parts upgrade info there. If I remember right my problem would go to just a line on some screens but grow a bit vertically on others.

Todd
 
http://www.biltronix.com/Star_Trek_08.html#GO8_parts

The deflection transistors in the heatsink with the fan mounted to it are wrong I believe if you used the 3716. Try and source the right ones. You could also try and find a schematic and trace the circuit back so that you can know that you have fixed everything all along the way. I am going to start working on my Tacscan monitor today so if any thoughts jump out I will let you know. It appears to be an x and y issue. I had another one that had a straight line that was a burnt trace on the paddle board.
 
I bought my ST directly from a video arcade in Santa Cruz, CA and I noticed that mine would have the same collapse that you pictured. The guy that maintained the arcade for the owners knew how to service the games and said that he would fix it for me before I bought it. When I returned with my truck to pick up the game, he did indeed fix it. When I asked him what it was, he said cold solder joints. All he did was pull the board and re-solder. It worked fine for years up until a few months ago when my flyback screen control caught fire (Burnt a hole thru the plastic casing on the screen control!) I have purchased another G08 from a fellow KLOVr but have not had the time to install it due to some family issues. I'm going to rebuild my G08 when I come across another HV section since the screen has zero burn and the deflection board has no issues. They are definitely difficult (stubborn) monitors!
 
Wow, it is such a pain to pull the board out of there cause you have to also pull the HV and the power transistor assembly, practically gut the back end. But in order to reflow properly for all practical purposes you have to do it at a bench and not just standing behind the cabinet with a portable iron.
If I could find adequate replacements for the MPSU40 and 60's, it'd be more worthwhile to pull the whole thing out and replace all the transistors as well in one fell swoop.
But the prices and availability of the transistors leads me to NTE171 and 240, but that's $70 in transistors. I guess NTE parts are disliked by many as well, but I'm just not finding much.
I was on Biltronix site and was all set to run his transistor subs but then I hit the snag on the MPSW92G availability. The 42G's can still be gotten.
I'm hoping my brand new 2n6259's weren't received faulty to begin with.
How I dread working on monitors.
 
Progress so far, but it's still fuxored.
www.zinfer.com/startrek.htm
http://www.youtube.com/watch?v=gLvfdeSmdzc&list=UUmZvw6W1WI5km8vd9QtfuHA&index=1&feature=plcp

Going to update the youtube vid with a tripod vid. Squished horizon, Image wraps, blooms, jumps left and right. Tried everything I know of.
Op-Amps can't do this right? I mean an op-amp either your getting deflection or not.
Acts like it needs a cap kit, but it was recapped the moment I began board repairs on the chassis.
I've adjusted the pots on the HV board. I've adjusted the pots on the XY timing/control board. Replaced all deflection transistors. Replaced the input protection boards' transistors, replaced bottlecap transistors. Ran all of Mongo's improvements as per his documentation.
 
I was told that blooming is usually caused by something failing in the HV section. Did you rebuild anything in the HV section of the G08 yet?
 
I know, that's what's so strange about all this. The whole thing was capped initially before I even started running repairs or replacement parts. And when caps let loose they usually do it with a bang.
So yea I'm kind of really stumped right now.
 
Back
Top Bottom