Hello everyone. My first first post here. Long time lurker!
A couple months back I acquired a Decca Super Gypsy MS1211. It’s working, and the cabinet is in ok condition for its age. The tube is producing a very crisp and sharp image.
I took the back off for the first time to have a peek in side. Lost of dust but was easy to clean out with a soft brush and a lens blower. Everything looks to be ok visually other than the main smoothing capacitor can appears to have leaked at one time, possibly decades ago. It has spilled out Electrolyte around its base, then ran down the timebase/power board across a few resistors all the way down under the line output transformers pins. It doesn’t appear to have caused damage. The substance has dried out in to a white powder that flakes off with a brush. I have cleaned most of it away at this point.
Should I replace the “leaked” capacitor? When I put the set on my Teletest Pro Cross-hatch screen there is a slight hum bar going on. (Like a water ripple effect) It gets worse the longer the set is running and warmed up.
I’m looking for any general tips or info on owning one of these? I would also like to ask if anyone has a circuit diagram or service manual that I can download and study?
Regards, Sam
I’m looking for any general tips or info on owning one of these? I would also like to ask if anyone has a circuit diagram or service manual that I can download and study?
Hi Sam, I've got the manufacturer's service manual for this TV, I'll get it scanned and will e-mail it to you. 👍
p.s.
Absolutely change the capacitor that has puked.
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Hi Sam, I've got the manufacturer's service manual for this TV, I'll get it scanned and will e-mail it to you.
p.s.
Absolutely change the capacitor that has puked.
Awesome! that would be perfect thanks! 😀
And yes, I think I'm going to replace the capacitor before I even power it back on.
(I took a few pictures for reference but couldn't work out how to upload and attach images?)
(I took a few pictures for reference but couldn't work out how to upload and attach images?
I'm surprised, it's a very simple system here, as it auto resizes the images.
There is an entire FAQ section here look for the one on "attachments to posts".
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
I'm surprised, it's a very simple system here, as it auto resizes the images.
There is an entire FAQ section here look for the one on "attachments to posts".
Yes, I've read that but i'm getting "No more attachments are allowed today".
Another thing I forgot to mention about the set. It has a very dirty and twitchy contrast control! I'm thinking of purchasing some servisol switch cleaner to hopefully sort that out.
These are necessary precautions all forums have in place, sadly due to the world we inhabit with porn and spam merchants trying to peddle their wares.
When you registered, you would have ticked a box stating you had read the rules. If you check item 4.1 it will all make sense.
As you've now made 3 posts, I think you will find you can now add photos. 👍
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
Hi Sam,
I've just scanned and e-mailed you the manufacturer's service manual, for the Decca Ms1211, MS1212, MS1216. The PDF was 12.1 MB, hopefully your inbox will be OK with that.
Look forward to following your exploits as you work on your TV.
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
I've just scanned and e-mailed you the manufacturer's service manual, for the Decca Ms1211, MS1212, MS1216. The PDF was 12.1 MB, hopefully your inbox will be OK with that.
Look forward to following your exploits as you work on your TV.
Received with thanks!, email replied to also.
Learnt a lot from it already!
It appears my suspect capacitor is a double one. Never actually seen one of these before but I knew they existed. It's labeled as C79 & C80. Both "sides" are 2000uf at 25v rating. C79 is the post bridge rectifier smoothing side and C80 is post regulator side (B+ supply?).
I'm most likely going to replace it with two 2200uf 25v high quality modern ones. I'm going to save the old one.
I've also discovered a dirty or tarnished fuse holder at location FS4. It also feels loose, possibly a dry joint under the PCB. It was giving me intermittent power up last week when I first opened the sets cover.
I'm going to upload some pictures of the unit later when I get some non-work project time. The images are still on my camera. My bench is currently occupied with some non vintage work so I won't be able to do much with Gypsy just yet hopefully at the weekend.
I'm looking forward to getting some proper television images showing on the set, I've only had a test generator connected up to it currently.
Some images of the internals, including closeups of the leak. 🤔 😬
So I've carefully removed the timebase board from the set. Removed suspect cap and bad loose fuse holder, ready for the new ones.
However I came to a few hurdles along the way. There was rust on both the anode cap contacts and CRT button. The spring contacts on the anode cap disintegrated and fell off after I removed it from the CRT. I was able to replace it with one from a modern B/W set from my spares box. The rubber cap is fine, I washed it and dried it before putting the new contacts in. I also cleaned most of the rust on the CRT anode. I'm hoping the rust hasn't affected the metal to glass vacuum seal much.
Back to the board, I discovered some sort of corrosion or high voltage corona/ozone damage to the end of the EHT cable. Curiosity got the better of me so I carefully removed the end caps on the HV rectifier (selenium diode?). I found some bad rusting to both the cable and the terminals. I didn't like the look of it so I decided to try clean up the joints and re-solder them. I cut back the cable a few millimetres and re-attached to the terminal. I also cleaned both end caps. I'm hoping this will still work after my cleanup. I'm sure there is a modern replacement for this part? I HV diode and a resistor perhaps? Or a NOS part?
It seems the set has been used in a damp environment at some point. That's to be expected since its a battery capable portable. There is no other rusting that I can see thankfully.
I was beginning to think I'd bitten of more than I can chew with this one, but we'll see how we go. I didn't pay all that much for it. I've never actually worked on a set this old as most of my collection consists of late 70's to early 80's portable mono sets. Plus 90's and early 2000s RGB scart colour sets for my retro games. (I'm in my early 30's BTW).
The new cap(s) and fuse holder arrived this morning. I'll try get an update up later this week.
-Sam
The corroded HV connections were a very common problem in coastal areas in Sydney where salt-laden air on the prevailing north-easterly breeze would permeate most homes.
Once it starts, corrosion generates corona and ozone, which is VERY corrosive.
Most manufacturers and reputable service engineers would seal the HV cap to the CRT with non-acid-cure silicone. Lacking that, petroleum jelly works quite well. I have also used heatsink-type silicone grease.
Re the CRT cap rust, yes, that WILL degrade the metal to glass seal and eventually admit gas, which will kill the CRT stone dead. I would paint the area with fish oil, which is a very effective anti-corrosive for steel alloys. It should also act to seal any possible leak.
Those selenium rectifier sticks are still available, no need to use a silicon diode string (although you could). You may be able to repair the one you have.
Whatever you do, avoid sharp pointed edges on the HV connections.
Many thanks for the tips and information irob2345. 👍
I going to look into using fish oil for the anode button rust. I am aware non-acidic silicone used on anode caps also. I was thinking of using dielectric grease under the cap, I've seen this used on a computer monitors and commercial/cctv monitors.
Managed to do some work on the set last week. The new caps and fuse holder are installed. I also ended up replacing a 1000uf 35v one in the frame stage. I have a few of these already in stock. I removed it from the board to see if there was any leakage, there is a small amount of fuzz is on its base. I suspect it's probably fine though.
With the set back together I held my breath and powered it up... It appears to be working fine thankfully. (Note the fact my unit has some of the decal/print worn off on the front plate)
I've not done a proper test and adjustment yet but I'm glad it still powering up ok. I've to set the unit aside for now so I can work on some other stuff. But I'm going to come back to this one in a month or so.
-Sam
