Tandberg 64 Servicing - UK Vintage Radio Repair and Restoration Discussion Forum

Sam · 7th Feb 2005, 5:46 pm

Hi. Just looking inside the Tandberg I bought from Ed Dinning, mainly because it developed noise on the left channel - a cap breaking down I think. A kind of bubbing, not crackling.

I was just wondering the likeihood of different caps being the problem:

1. The Hunts Moldseals (world domination on crap caps, or what!) - seem to all be 150v or 600v types, but I guess up to their usual standard of excellence.

2. Siemens electolytics - these are in tall thin metal cans, about 14mm in diameter, 50mm in height. They are all 16uF, 350v types.

3. Small metal cased caps with a plastic sheath at the bottom, 25uF.

4. Little gold-foil covered caps, 400v, 0.022uF/0.047uF-ish values, made by miniprint. Never seen these before. Guess they must be continental ones.

I guess the Hunts are the most likley culprits, but are the other ones reliable?

Non-electrical question now. What do people recommend I use for the bearings? Grease or Oil?

Sam

Ed_Dinning · 7th Feb 2005, 6:04 pm

Hi Sam, all small caps can be rubbish, see the thread on crap caps. The finger test often works ~ with set off after it has been running and one hand in pocket, gently feel resistors in series with caps for heat. The modern version is to borrow an IR camera and look at them for heating.
Fault finding like this can be a pain on low level circuitts where the cap going down does little other than cause noise or remove the signal. A scope is often the best tool here, couldpled with a knitting needle to poke the offending items.
On lubrication, see what the manual says. Grease may be too thick for some bearings and will cause the recorder to run slow. SMALL amounts of 3in1 will do no harm. If sintered bronze bushes are used these were usually impregnated for life. After 40 years they will benefit from being stood in warm 3in1 for a week or so then drained.
HTH, Ed

7th Feb 2005, 5:46 pm	#1
Sam Hexode Join Date: Apr 2003 Location: Higham-on-the-Hill, Leicestershire, UK. Posts: 338	Tandberg 64 Servicing Hi. Just looking inside the Tandberg I bought from Ed Dinning, mainly because it developed noise on the left channel - a cap breaking down I think. A kind of bubbing, not crackling. I was just wondering the likeihood of different caps being the problem: 1. The Hunts Moldseals (world domination on crap caps, or what!) - seem to all be 150v or 600v types, but I guess up to their usual standard of excellence. 2. Siemens electolytics - these are in tall thin metal cans, about 14mm in diameter, 50mm in height. They are all 16uF, 350v types. 3. Small metal cased caps with a plastic sheath at the bottom, 25uF. 4. Little gold-foil covered caps, 400v, 0.022uF/0.047uF-ish values, made by miniprint. Never seen these before. Guess they must be continental ones. I guess the Hunts are the most likley culprits, but are the other ones reliable? Non-electrical question now. What do people recommend I use for the bearings? Grease or Oil? Sam __________________ Can he lead a Normal life, Doctor? No, he will be ... an Engineer.

7th Feb 2005, 6:04 pm	#2
Ed_Dinning Dekatron Join Date: Jan 2004 Location: Newcastle upon Tyne, Tyne & Wear, UK. Posts: 8,194	Re: Tandberg 64 Servicing Hi Sam, all small caps can be rubbish, see the thread on crap caps. The finger test often works ~ with set off after it has been running and one hand in pocket, gently feel resistors in series with caps for heat. The modern version is to borrow an IR camera and look at them for heating. Fault finding like this can be a pain on low level circuitts where the cap going down does little other than cause noise or remove the signal. A scope is often the best tool here, couldpled with a knitting needle to poke the offending items. On lubrication, see what the manual says. Grease may be too thick for some bearings and will cause the recorder to run slow. SMALL amounts of 3in1 will do no harm. If sintered bronze bushes are used these were usually impregnated for life. After 40 years they will benefit from being stood in warm 3in1 for a week or so then drained. HTH, Ed