K6100 bad focus block maybe?

gamefixer

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So I'm messing with a K6100 in a Space Duel. When its cold the picture is nice and sharp. As it warms up it loses focus. The focus control has very little effect on the screen. Seems to me that I should be able to measure the focus voltage with a HV probe, no?

All connections behind the block are good, the 3 pin connector also checks out. b+ is 180VDC. monitor has been capped.

I'm thinking bad focus block or bad tube.

Matt
 
Yes you can measure the focus voltage with a high voltage probe.

Thats kinda what I thought. I never really bothered in the past though. I just want to see if the focus voltage is traveling while I turn the pot. That will narrow down my problem.

Matt
 
Did you buy the one from RacerX or is this a different one? My wife OK'd me to get RacerX's. I sent him some email and a PM. If you got it, then it is a lost cause. :)
 
Did you buy the one from RacerX or is this a different one? My wife OK'd me to get RacerX's. I sent him some email and a PM. If you got it, then it is a lost cause. :)

Nope, its a different one. I found one on CL that I couldn't pass up. It had no picture when I got it but a few cold solder joints and an LV6100 (Mark's LV Board) and I had a picture. About 5 minutes later the focus started to waft....

Matt
 
Nope, its a different one. I found one on CL that I couldn't pass up. It had no picture when I got it but a few cold solder joints and an LV6100 (Mark's LV Board) and I had a picture. About 5 minutes later the focus started to waft....

Matt

Well, RacerX got back to me, so I will be working on that 6100 very soon. I'm going to go pickup that space duel tomorrow. :)

-VJ
 
Matt,

I was thinking about my original Space Duel 6100 repair this morning while I couldn't sleep (anticipation getting another one of course). Anyway, it reminded me that my focus circuit sucked and needed a couple repairs.

The Molex connector that connected the focus assembly to the neck board was burned up, and one of the cables broke off while I was looking at it.

IMG_0209.jpg


Also, the red wire ended up breaking off from the neck board wile looking at it. It was literally held on by a single strand that broke. So inspect all of those wire connections. Two other thoughts are to make sure the wires are connected to the pins on the focus assembly well since they are known to come loose under those boots. The last thing is to check the CRT socket pin for focus and the solder joints on the bottom side.

I figure you may know and have done all of this, but thought I would mention it in case something got overlooked. Hopefully it isn't the tube.

Good Luck,

-VJ
 
Last edited:
Matt,

I was thinking about my original Space Duel 6100 repair this morning while I couldn't sleep (anticipation getting another one of course). Anyway, it reminded me that my focus circuit sucked and needed a couple repairs.

The Molex connector that connected the focus assembly to the neck board was burned up, and one of the cables broke off while I was looking at it.

Also, the red wire ended up breaking off from the neck board wile looking at it. It was literally held on by a single strand that broke. So inspect all of those wire connections. Two other thoughts are to make sure the wires are connected to the pins on the focus assembly well since they are known to come loose. The last thing is to check the CRT socket pin for focus and the solder joints on the bottom side.

I figure you may know and have done all of this, but thought I would mention it in case something got overlooked.

Good Luck,

-VJ

Yup, all of that checks out. I'm going to try to remember to grab my high voltage probe from the shop in Monday. With that I can at least verify that the focus block is good or bad.

Matt
 
I had a 6100 with focus issues...it turned out to be a bad tube socket on the neckboard. I've also had this same issue (bad socket) on several K7000's and G-O7's. Do you have another neckboard.....easy enough swap to rule it out.

Edward
 
I had a 6100 with focus issues...it turned out to be a bad tube socket on the neckboard. I've also had this same issue (bad socket) on several K7000's and G-O7's. Do you have another neckboard.....easy enough swap to rule it out.

Edward

No other hardware, this is the only k6100 I have in the house at the moment.

Matt
 
I'm having this exact same problem on my Star Wars. Let me know if you figure it out.


I'll try to remember to post my results. I'm going to run over to the shop to grab my High Voltage probe and Exidy is sending me a neck board and an HV cage. I really dont want it to be the picture tube but since I've only seen this two other times and BOTH of them were bad tubes (late 80's) I'm not feeling good about it.

Matt
 
Well... My issue is not the high voltage cage/focus block. I was able to measure 3.5kv up to about 6kv on the focus wire so the focus block is fine. I checked my voltage right where the wire solders to the neck socket.

SO I started screwing around with the focux pin on the tube and the contact in the socket. After I bent the contact out and did some minor scraping on the pin it worked better but still went out of focus. I was going to pull the plastic adapter off of the tube but felt like doing other things...

I'll post the results after I pull the adapter off and clean the pin.

Matt
 
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