"no matter what it takes" (CTC169/Proscan tubes)

If it can work for a number of days with no arcing, maybe you have a solution that works. There is not much else you can do, if you cannot have the original or equivalent parts.

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Jerry G. ======

This is the second time I've had this paroblem: it arcs between the two focus pins. This socket is peculiar to their IDTVs, a bunch of the Proscan line and a few regular CTC169s. Obviously a CRT socket replacement was in order but there were none to be had. I was told to do whatever it takes. This means almost unlimited resources, as long as it's done today. We can't wait for a socket or we risk the need to refund.

When I need to be a hillbilly I try to be the best one I can.

After disassembling the socket and removing the electrodes I cleaned the plastic with acetone. In one of the tunnels in which the focus electrodes reside there is still a brown spot. As Alex Harvey said "I flipped open a packet of cigarettes and considered the situation".

Removing all the material between the pins and replacing it would do it, but there is no facility for that, nor is there time for anything to dry overnight.

I always look for the safest, most effective, reliable and REVERSIBLE modification possible.

I removed the pingrabbers from the socket assy, and had a good hard look at them. I then decided to straighten the bend they put in it, put in my own to retract the grabber about 3 mm from where it used to be in relation to the plane of the socket. I then found some 16 ga. wire with thicker insulation (like the thicker yoke wires). I took just about 3mm of insulation from that and put it on the CRT pin.

I felt the insulation engage the body of the socket when I reinstalled it. It kinda dropped when I got it really aligned. I checked and there was no gap between the pin protector and the socket. The "drop" was about the same as the length of the insulation.

Set fired up and did not arc. I effectively moved the arcing points 3 mm away from each other.

In your opinion, did I come up with a solution or did I make a mess waiting to happen ?

Thanks in advance.

JURB

two

as

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in

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3mm

reinstalled

there

Given the situation (time pressure and lack of spares) I think you have done a good job, cetainly it's hard to think of anything better in those circumstances. CRT sockets can and do cause problems. Leave it on and see what happens. At best it'll be Ok; at worst you'll have to look at getting a new part if the mod fails.

Cleaning all the socket and pin contacts with alcohol or brasso may help also. (make that a JAR of brasso ;-))

Ben

You do what it takes. I recall a popular stereo system which used a single triode pentode as the output amplifier for each channel. After a few months use the tubes increased in gain (normal) and started to oscillate at a supersonic frequency, burning up the output transformers (abnormal). I used to solder a tin shield around the bottom half of the tube base and replace the transformers which always seemed to fix them for good. I also contacted the maker and alerted them to the problem.

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N

Assuming the run and standby B+ are correct, ~140V, then the focus divider is bad. Very common failure item on these sets, especially after B+ had been running high due to the capacitor problems in the power supply.

After the focus block is replaced, usually the crt socket should also be replaced to remove the carbon tracing.

Very common, fixed lots of them with this issue.

David

snipped-for-privacy@aol.com wrote:

two

as

put

in

with

3mm

reinstalled

there

" snipped-for-privacy@aol.com" bravely wrote to "All" (16 May 05 23:17:35) --- on the heady topic of ""no matter what it takes" (CTC169/Proscan tubes)"

ZZ> From: snipped-for-privacy@aol.com ZZ> Xref: aeinews sci.electronics.repair:48416

[,,,] ZZ> When I need to be a hillbilly I try to be the best one I can.

ZZ> After disassembling the socket and removing the electrodes I cleaned ZZ> the plastic with acetone. In one of the tunnels in which the focus ZZ> electrodes reside there is still a brown spot. As Alex Harvey said "I ZZ> flipped open a packet of cigarettes and considered the situation". [,,,]

JURB,

You were really close to the solution when you mentioned the acetone. The idea would be to use some nail polish to cover the brown spot. The clear stuff would be best. Definitely stay away from the sparkly metalic finishes. Girls around the office always have some in their purse. Who knows, you might have got a phone number too. ;-)

A*s*i*m*o*v

... "Bother!" said Pooh, as he saw the sparks and smelled the smoke.

Ingenious fix. One thing I would have done, is alert the owner that a new socket was in order, that the fix 'might' be temporary...tried to get authorization to order one (on his dime) 'just in case.'

jak

Hi- I have a 46" projo with a CTC169 chassis I'm selling as parts. Please let me know if I can help with anything. Thanks

moonlite