Maggie roundie combo

[ctc17]

I have been using those TO220 package dual diodes you find in modern switching mode power supplies. Mostly because I have extras. They work great.

Every tube caddy I have run into has a few of these in it. They must have been a common fail even back in the day. They are only rated at 1ma so the new high current diodes should last.

[wa2ise]

Originally Posted by ctc17

I have been using those TO220 package dual diodes you find in modern switching mode power supplies. Mostly because I have extras. They work great.

Those switching power supplies run at or higher frequencies than TV set horizontal circuits (15734HZ). So those diodes would be an excellent choice.

[DaveWM]

back in, no HV, HOT starts to red plate. Hmm horz osc filament not on. move tube around and it comes back, HV comes back, wiggle it again, HV goes out. So it looks like the filament connection to the 6FQ7 is intermittant (prob what side lined it in the 1st place). I tried a different tube just to be sure it was not the tube itself, same deal. So I will pull the chassis and do a close up exam, my guess is a ground stake (if there is one that just feeds this tube) or maybe a loose contact pin socket. What ever it is I dont think it will be too much. Plus I have some NOS sockets that I would be willing to just replace it, esp on such an important tube. I have had tube socket failure before on this type, last time was the vert osc of a predicta. the bridge between the tube PCB pin and the actual socket can fracture, very hard to see, and the only real way to catch it is with a socket test adapter, since touching the pin sockets with a test lead will often close the cap and make it look good. I prob just got lucky the 1st time after checking the tube, and the install happened to be good (when the set was working after the inital check out). I do recal the HV was not there when I got it and I did a wiggle of the tube and it came back. Its just a bit too sensitive as is.

[DaveWM]

good vert/horz sync, good color, just some intermittant snow so prob a dirty tuner, but looking good. I will take a close look at the 6FQ7 socket next time I have it on the bench.

[DaveWM]

reflowed the 4/5 pins on that socket they looked a little cold. I also reflowed the ground stakes. Working ok, but will wait until tonight for darkness and see if I can wiggle it OFF now. I used my pick to also tighten up the sockets.

while I have good light out in the garage I plan to pull the tuner case off (I found one that fit) and clean the tuner contacts. the pots have been cleaned and lubed but for the pots on the back, I am going to leave them be for now since I dont think they get much use anyway.

Still have to find a place to mount the cathode fuse for fusing and checking the HOT.