Sylvania console

[Charlie]

That chassis pic is quite dusty. You cleaned all the dust out of there, right?

One of my roundies had a really dim picture when I first got it... kinda snowy too. Had lots of dust and cleaning it brought everything back to life!

[sampson159]

i ve had bad triplers cause all kind of strange problems with these sets.once at the shop,we had a sylvania that was similiar.all voltages were correct yet a very dim picture.had to turn out the lights to see anything,dim even then.crt checked good 28-29k at the anode.heater volts were 6+ volts.we were thinking crt.though it checked good,it could be bad?dave jones came by and told us the tripler wasnt defective-it was the wrong one for the set.it sure was!new unit,just the wrong eeg replacement.also service switchs are suspect.pull modules and look ffor breaks especially around the brighness and agc controls.lytics are another problem.your set has a washout in the crt.check plugs for the yoke and convergence.cold joints and check all grounds on the modules.make sure you screw the modules back down.we would get some comebacks because of unusual lines in the picture because of loose modules.these are fairly easy sets to repair.love them!!!that washout on the crt is an issue.good luck with this and keep us in tune as to your progress.i have a module or two for that set.also a rebuilt crt.not a dmp though.

[bgadow]

One of the problems with the ss Sylvania I have is that the setup switch barely fits through the hole in the back. When installing that cover it is very easy to miss the hole and pull the switch out of the circuit board. That happened on mine and lead to an intermittent in the video. When it acted up the screen was very dark and had a "negative" look.

[ctc17]

Yep all socketed transistors. Brings back memorys, all the red TO220 style. I checked, dont have the sams for thats set, bummer.
You could try wiggling some of the transistors around in the sockets. If I remember one common issue with mine was poor contact in the transistor sockets.

[DaveWM]

there are 3 main boards

IF
Chroma
deflection


did the wiggle thing on a bunch of transistors
checked the video amp, blanking and some other transistor on the chorma board, all tested good.

cycled the service switch several times.


I may need to pop for a Sams if no one has one here on the boards. I have no idea what to do next short of checking all the little electro caps. I dont have an esr meter so I would need to take them out of circuit for my old heath tester (I assume the ESR meter does not find a shorted or leaky cap anyway). Are those worth the 150-200$ I see them listed for, or am I just better off pulling the cap and testing in my old heath kit tester?

I am assuming I can concentrate on the chroma board since I am pretty sure the vert sweep is working and I have HV so the horz is working, I am getting good sound so I assume the IF board is ok.

My next course of action was to trace the brightness control pot wires the the PCB and the G1 grid wires to try to understand high bias is set on the CRT (that is with out a schematic) for now.

[Reece]

I had an all SS Sylvania a couple of years newer than yours that your chassis picture reminds me of. After some years the tripler tended to arc over but I scraped off the carbon and siliconed up the sharp arcing-prone points on it and it ran for a number of years. I eventually replaced the tripler but an ongoing problem was the two heat sinked transistors seen just to the left of the HV section. They plug into sockets and the connection was sometimes iffy as they draw some current. One of them, the one on the right in the picture, would blow after a few months. Too much heat. I ended up sort of "corrugating" the transistor leads like a bobby pin so they'd make better contact, and putting plenty of heat sink compound on the transistor cases. I also made up and screwed on some aluminum cooling fins to the heat sinks. After that I had little trouble with those parts.

[Charlie]

Wish I wasn't STILL stuck out here at anchor on the ship... if that set is from 75, I likely have the Sams for it. If I make it home before you find another, I'll dig it out... but that could be a few days....

[DaveWM]

hope you get back soon Charlie, I will hold of on buying a sams till I hear back from you.

This beast is HEAVY...

the radio works fine, but the 8 track is missing its belt (I dont have any 8 track any more, lost my old fake alligator skinned 8 track box back in the 70's, had some good ones led zep, jetho tull ,the who, you get the picture).

Popped off the radio bezel to realign the dial scale, greeted with several nice bug cases.... yuk....

[Charlie]

The 8-track doesn't work???? Aw man... what a shame!!!

[DaveWM]

yea I miss that un even speed and constant head alignment

[DaveWM]

Charlie I hope you get in port soon, going no where fast on this beast.

[Charlie]

YOu and me both! I was supposed to get off a week ago! We're still anchored in the same spot... 5 miles off Galveston... watching all the foreign flag ships go in and out! As soon as I get home, I will go dig out that Sams and send to you.

[Findm-Keepm]

On those Sylvanias, I can offer up this: check the brightness limiter control settings. (R294 on my factory schematic, should be near the service switch)

After that, I'd be looking at voltages - Sylvania marked the boards with the voltage - +/- 10 percent should be good.

There is a video driver transistor that the service switch affects - it's Q214 on my schematic. It feeds all of the RGB output amp transistors. The emitter voltage should vary a bit (~ 15V, varies a volt or so) when the service switch is cycled.

It seems your +200V supply is working, and you have boost, so check the 330K 1W resistor off of the screen controls. Often this will open and cause problems. Power down when checking, because one side will have boost (+1100V) on it if it's open.

I'm working without benefit of my service notes, which I can look at tomorrow. This should get you started though.

Cheers,

[Findm-Keepm]

FYI - the CRT bias control is fed with +200V which feeds through a 220K resistor, then the pot, and finally through a 39K resistor to ground. I'd check the wiper of the bias pot for a varying +30 to +100V. If no voltage, then the bias pot and two resistors should be checked. If this is good, check the 3.9K resistor that feeds from the crt bias pot to the CRT G1.

Hope this helps,

[DaveWM]

I will get on it Brian, thanks for the pointers.