Combwork
07-01-2009, 07:59 AM
Hi,
Despite being at least 20 years old this 25" set works well. But last night it fired up with a good picture, but also a ticking sound from the back; about once every couple of seconds. With the back of in the dark I saw a spark from the casing of the line output transformer to a middle size capasitor. It seemed to the side of the cap but maybe it was tracking through dust. I cleaned it, gave it a squirt of switch cleaner to wash anything off that was stuck to, fired the set up and all seemed well. Then after a few minutes the ticking started again; only once in about thirty seconds but still there so I bent the capacitor away from the LOPT and all seemed well. Except now there was a continious fizzing sound from the EHT cap on the tube, the kind of sound you get if you turn the EHT up too high. I turned the set off but wasn't able to pull the connector off so put a good layer of plain silicone sealer under the rubber cap. There were traces of old sealer under it anyway; no servicing has been done on this set so I guess it was there from new.
For years there has occasionally been a few loud 'cracks' from the back, but after about 5 minutes they stop. I've just left it; maybe it was caused by damp? I've left the sealing on the EHT cap overnight to give it a chance to fully cure. If the fizzing has gone do you reckon this is OK? If I could find the EHT voltage adjuster I'd back it down a bit; better a slightly softer picture than anything arcing over; I had this with an old tube color TV and it's not funny........
Despite being at least 20 years old this 25" set works well. But last night it fired up with a good picture, but also a ticking sound from the back; about once every couple of seconds. With the back of in the dark I saw a spark from the casing of the line output transformer to a middle size capasitor. It seemed to the side of the cap but maybe it was tracking through dust. I cleaned it, gave it a squirt of switch cleaner to wash anything off that was stuck to, fired the set up and all seemed well. Then after a few minutes the ticking started again; only once in about thirty seconds but still there so I bent the capacitor away from the LOPT and all seemed well. Except now there was a continious fizzing sound from the EHT cap on the tube, the kind of sound you get if you turn the EHT up too high. I turned the set off but wasn't able to pull the connector off so put a good layer of plain silicone sealer under the rubber cap. There were traces of old sealer under it anyway; no servicing has been done on this set so I guess it was there from new.
For years there has occasionally been a few loud 'cracks' from the back, but after about 5 minutes they stop. I've just left it; maybe it was caused by damp? I've left the sealing on the EHT cap overnight to give it a chance to fully cure. If the fizzing has gone do you reckon this is OK? If I could find the EHT voltage adjuster I'd back it down a bit; better a slightly softer picture than anything arcing over; I had this with an old tube color TV and it's not funny........