My old faithful Dynatron TV.48V packed up today!
Was it really 2011 when I got this set?! how time flies! It was the subject of this thread:
https://www.vintage-radio.net/forum/...ad.php?t=74776
Since my somewhat rudimentary repairs back then the set has housed my standards converter and DVD/VCR which provides signals for the downstairs 405 sets.
I never really finished the poor old Dynatron I meant to fix the LOPT cover and refit the lower part of the back cover to cover the tuner but modified to allow access to the VCR and make final tweaks to get the frame linearity better, I think the frame output valve is a bit slow warming as it improves after a run...
Anyway today I needed some 405 signals so I powered the converter and turned on the set.
(I use the set to select / display what is coming out of the converter before I send the signal to the desired set)
Sound.. 405 whistle.. No picture! After I had got over my surprise I took the back off and looked inside. lots of dust and a huge cobweb!
I checked for EHT and the arc seemed about right from the rectifier top cap but I couldn't see the rectifier alight.
My first thoughts were that the LOPT had finally given in But I thought it would be worth trying a valve...
I looked around the chassis thinking how dusty it had become when I noticed another valve not alight.. I switched off and pulled the valve, A Mazda 6F28 it looked quite black and heat stained plus the getter looked thin and dull.
Nipping into the workshop I trawled through my box of second-hand telly valves, nothing! everything but!
I checked on line because I wondered if an EF80 may do but the valve museum says not.
Then I looked in my valve rack (which are mainly radio valves) Success I have a new one!
I fitted the valve switched on and Bingo the set came to life! So the EHT rec must have been alight all along!
Just like the old days of field service! have a look for the obvious first!
It's got a valve gorn mate!
Quick dust out, back on, spin it round...
Exit.. (not perused by a bear..
)
The LOPT still waits patiently for its Perspex...
Rich