10-05-2019, 06:03 PM
Another gray weather day so more work on the 19A. Incredible thunder storm this afternoon, big bangs and hail, May? Really?
Found a set of valves, an ECH35 instead of the CCH35, a Mazda EF39 that still has the metalising so it may not oscillate, and a short proper EBL31 so that the top cap connector will reach and fit. The original AZ31 is OK. I seem to have lots of red Mullard EF39s and they all oscillate badly, but then they all need re-metalising or used in screening cans.
Onto the isolation transformer via a lamp limiter, no bangs or smoke, a fading glow so give it the beans and there are sounds.
Radio 4 on long wave tunes in, a few whistles and crackles but there is life in the set.
A quick twiddle of the IF transformers and it improves but there is an obvious problem with the frequency changer and the IF amp valves not making good contact with their sockets. Inspecting the sockets reveals several broken pins, they are the horrible paxolin ones with the brittle brass connectors. Two new octal sockets need fitting, luckily I found the last two with the same fixing centers as the originals. Pick off the connections, the usual over wrapped wires are a pain, drill out the rivets and fit new with nuts and bolts.
Refit all the components and wires, power it up, and it works but its coming and going, the HT is intermittent. The wirewound smoothing resistor has a bright spot and is in need of replacing. 2K5, 10W not in stock, make it up with three 5W, 1K, 1,2K and a 300 ohm in series and a tag strip to hold them.
Back on and it is working really rather well, radio 4 longwave, plenty of medium wave stations, the BBC seem obsessed with football, even some short wave stations which is surprising with the workshop short indoor aerial. HT is a little low at 209V, should be 230V but it will be enough. Run for an hour, nothing distressed, the electrolytics are still cold.
It needs a full alignment of course but the If transformers are peaking "by ear" so that is encouraging. Amazing how well it sounds for what is only a 3 valve plus rectifier set. The EBL31 is a super valve for economy radios. I will finish the chassis and put it away whilst I get stuck in to the cabinet.
Not come up with any good ideas about that troublesome trim yet and not decided whether to do a see-through back or a hardboard one, a lot depends on the woodwork, if it comes good and I can lose the stains I will re-polish it and keep it original, otherwise it will be a colour paint job with perspex back. Its a good looking chassis, shame to hide it away.
Found a set of valves, an ECH35 instead of the CCH35, a Mazda EF39 that still has the metalising so it may not oscillate, and a short proper EBL31 so that the top cap connector will reach and fit. The original AZ31 is OK. I seem to have lots of red Mullard EF39s and they all oscillate badly, but then they all need re-metalising or used in screening cans.
Onto the isolation transformer via a lamp limiter, no bangs or smoke, a fading glow so give it the beans and there are sounds.
Radio 4 on long wave tunes in, a few whistles and crackles but there is life in the set.
A quick twiddle of the IF transformers and it improves but there is an obvious problem with the frequency changer and the IF amp valves not making good contact with their sockets. Inspecting the sockets reveals several broken pins, they are the horrible paxolin ones with the brittle brass connectors. Two new octal sockets need fitting, luckily I found the last two with the same fixing centers as the originals. Pick off the connections, the usual over wrapped wires are a pain, drill out the rivets and fit new with nuts and bolts.
Refit all the components and wires, power it up, and it works but its coming and going, the HT is intermittent. The wirewound smoothing resistor has a bright spot and is in need of replacing. 2K5, 10W not in stock, make it up with three 5W, 1K, 1,2K and a 300 ohm in series and a tag strip to hold them.
Back on and it is working really rather well, radio 4 longwave, plenty of medium wave stations, the BBC seem obsessed with football, even some short wave stations which is surprising with the workshop short indoor aerial. HT is a little low at 209V, should be 230V but it will be enough. Run for an hour, nothing distressed, the electrolytics are still cold.
It needs a full alignment of course but the If transformers are peaking "by ear" so that is encouraging. Amazing how well it sounds for what is only a 3 valve plus rectifier set. The EBL31 is a super valve for economy radios. I will finish the chassis and put it away whilst I get stuck in to the cabinet.
Not come up with any good ideas about that troublesome trim yet and not decided whether to do a see-through back or a hardboard one, a lot depends on the woodwork, if it comes good and I can lose the stains I will re-polish it and keep it original, otherwise it will be a colour paint job with perspex back. Its a good looking chassis, shame to hide it away.
Boater Sam.
