I have been working my way through the faults on the 3500 "superbanger" that I asked for help with recently. I have three decoder panels one that came with the set and two spare. I was fairly sure that the fault was on the decoder panels rather than the IF or line panel but found it odd that I had three faulty panels.
So before I go and get my scope out I decided to test the panels in my working Ferguson 3000. I haven't run the 3000 for some time so today I decided to give it a go and test the panels. This lead to me repairing the tuner a job that has been waiting for me to get around to for some time. As often with jobs that wait once you decide to do them it takes moments and makes me ashamed that I have been putting them off for so long!
So after proving that all three decoder panels are faulty I decided to sort out some of the other sets that have been waiting for little jobs to be done!
First was the Invicta 368 this has had low height for some time and an annoying frame jitter. One resistor and a tweak of the preset contrast saw it working. Then came the Murphy This I overhauled many years ago but the last time I tried it about 2 years ago I discovered it had frame collapse. Today I found the 6/30FL2 was cracked . A replacement didn't cure the fault a second replacement did. Not all NOS valves are good it seems...
Then I ran up the various Thorn sets on the other side of the workshop. A few jobs to do there another day the 950 has bottom fold up the 1400 has a centre foldup depending on brightness the 1500 has gone dead and the KB Deep scene also lacks height.
I enjoyed my day in the workshop and plan to make time again soon!
Fixed it for you Rich 👍
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Not at all Rich, we've all done it. Besides, you're getting used to a forum interface quite removed from the one you're used to over on UKVRRR. Anyway, good to see you're having fun in the workshop. 👍
CrustyTV Television Shop: Take a virtual tour
Crusty's TV/VCR Collection: View my collection
Crustys Youtube Channel: My stuff
Crusty's 70s Lounge: Take a peek
Wow, there's something wonderful about shelf-loads of working TVs. You can't get that effect with radios.
The pictures are better on a radio.............................................
Now who made that quote, it’s quite a famous one.
Frank
A quick google brings these:
"I prefer radio to TV because the pictures are better" Alistair Cooke
"It's like TV but the pictures are better" Clive Anderson
Letter from America was a programme not to missed!
Two names there that I used to watch and listen to, yes Letter from America was excellent.
Frank
Another day yesterday spent sorting out the workshop, Some of these sets haven't been powered up in years. It surprised me how many worked without any work. The two Thorn portables worked without even any adjustment.
The GEC put up more of a fight though. First of all it came on with a fairly poor rolling picture. Then after a short while the picture improved no end. Still rolling though with no frame sync, the width then dropped, and the picture went off. Through the screening can of the line output stage I could see a bright blue glow, the line output valve was not happy! I fitted a replacement which brought the picture back, but then it was the turn of the EHT rectifier to glow blue! The rolling picture remained though and after a little while the blue glow diminished to a very low level, so I guess the rect had recovered a bit?
I squint at the circuit showed a D77 / EB91 as the frame sync pulse shaper, so I thought it would be worth a try replacing it. I was fairly surprised to find it provided a complete cure! I then gave the set a good run, watching some old programmes on DVD. The set has come back to life a treat!
Next job is a couple of Thorn 1400s. One is untouched as I bought it with if I remember rightly a fair few faults, the other is the Marconi one which works but has a strange cramping fault affecting the middle of the picture affected by the brightness and if I remember rightly wins the award for most horribly bodged dropper!
Hopefully, you will no longer have the blues over the GEC. 😉
To understand the black art of electronics is to understand witchcraft. Andrew.
Next job is a couple of Thorn 1400s. One is untouched as I bought it with if I remember rightly a fair few faults, the other is the Marconi one which works but has a strange cramping fault affecting the middle of the picture affected by the brightness
If that's line cramping there was a mod issued for that. Check R70, it's value was changed from 39k to 33k during production.
John.
@jayceebee Thanks I will check that. The resistance value must be fairly critical as that's not much of a change?
Goodness me Rich, you have been very busy with the sets of late!
@cathovisor Hi Mike yes I have had more time lately for my hobby and I decided to go through the set in my collection and get them going as a few had packed up and a lot hadn't been powered up for a few years.
Over the last few days I have been sorting out the portables. The 12" 1590 needed the sound amp repairing and had an intermittent fuse holder. The 14" 1591 worked for a second then the tuner cams fell apart followed by the S correction cap going short resulting in a blown LT fuse and a stink of hot plastic. This set was another skip find some time ago. Judging by the spatter pattern in the dust it looks as it it was out in the rain for a while. I did check the LT was correct on both sets as it can drift and over-run the tube heaters. Luckily both sets have excellent tubes!
I had all the sets up and running today the 1500 then decided to lose line lock! There's always one has to spoil it!
