Well, great progress today. I replaced D701-D704 OA81s with OA91s even though only 1 of the diodes was faulty (read 0.5V instead of 0.33 in diode mode on my meter). As a precaution, I also took out and measured C708 and C709 500 pF silver foil - both were spot on, but very fragile, so I replaced them each with 2 x 270pF in parallel 1% NP0/COG and voila - I have stupendous undistorted stereo FM. I also replaced Q903 with a MJE15032 about 2 years ago when I first started out on this journey that I forgot to mention. The stereo indicator light is not working so I will have to address that. Luckily, it looks like I can do that with an LED. I still have to check out the phono section and then do an overall distortion etc measurement - that will have to wait until after the camping trip though.
Some of the tone control pots and switches are quite scratchy, so I'm going to have to intervene with the switch cleaner. However, I am nervous because these are very old components, and I don't know if they have plastic bits that will succumb to a modern switch cleaner—ditto the pots. Anyone with experience in this regard?
Interestingly, despite the rated power of 40W per channel (the transformer is quite hefty!), the main reservoir caps are only 2 x 1000uF 100V - so total 2000uF as this is a single rail 'singleton' amplifier. I might consider replacing the rectifiers with something more substantial and perhaps going for 2 x 2200 uF each - but then I reckon I'm not being true to the original.
Anyway, I am very pleased the FM tuner is working on what is a close to 60-year-old classic receiver! I'll hook this thing up to the Dali's a little later on and disturb the wife's TV watching 😉
Some of the tone control pots and switches are quite scratchy, so I'm going to have to intervene with the switch cleaner. However, I am nervous because these are very old components, and I don't know if they have plastic bits that will succumb to a modern switch cleaner—ditto the pots. Anyone with experience in this regard?
Interestingly, despite the rated power of 40W per channel (the transformer is quite hefty!), the main reservoir caps are only 2 x 1000uF 100V - so total 2000uF as this is a single rail 'singleton' amplifier. I might consider replacing the rectifiers with something more substantial and perhaps going for 2 x 2200 uF each - but then I reckon I'm not being true to the original.
Anyway, I am very pleased the FM tuner is working on what is a close to 60-year-old classic receiver! I'll hook this thing up to the Dali's a little later on and disturb the wife's TV watching 😉
Use LEDs for FM Stereo beacons. If it uses a chip, they are rated for 40 mA approx. I'm tired of replacing these ICs because someone installed a higher current lamp.
Try LPS Micro-X if you can get it, or something similar. I haven't had any problems using it.
The signal diodes for the MPX are germanium (should be) and should measure 0.2 ~ 0.3 VDC drop on your meter. I'm not that familiar with Pro-Electron part numbers, it's just a standard germanium signal diode, nothing special.
Try LPS Micro-X if you can get it, or something similar. I haven't had any problems using it.
The signal diodes for the MPX are germanium (should be) and should measure 0.2 ~ 0.3 VDC drop on your meter. I'm not that familiar with Pro-Electron part numbers, it's just a standard germanium signal diode, nothing special.
Steam iron: Wouldn't steam.
Cleaning procedure helped a little: Oust descaling solution did the trick.
Instructions stated warm (hand hot) iron, unplug, allow fluid to drip out: Nothing comes out unless iron is hot and steaming.
Warning - I suspect the steam coming out is mildly acidic: Next time I will perform the descaling procedure outside.
Cleaning procedure helped a little: Oust descaling solution did the trick.
Instructions stated warm (hand hot) iron, unplug, allow fluid to drip out: Nothing comes out unless iron is hot and steaming.
Warning - I suspect the steam coming out is mildly acidic: Next time I will perform the descaling procedure outside.
I used to add a little vinegar in my steam iron...and flush it after cooling, so little scale.
It depends on the hardness of the water...
Then the thermostat got erratic, repair shop said it will leak after new thermostat, so I bought a new regular iron, and a pump type plant sprayer...
I suspect a high temperature sealant was used, and the repair shop did not know about it, or would have to break something during repair.
It is old, from 2008, I paid $4 new at a store closure sale...and I expect the repair may have cost me $2 to replace a 30 cent thermostat.
It still steams, I use it sometimes when I feel like, but the new iron was like $5, and it works okay.
It depends on the hardness of the water...
Then the thermostat got erratic, repair shop said it will leak after new thermostat, so I bought a new regular iron, and a pump type plant sprayer...
I suspect a high temperature sealant was used, and the repair shop did not know about it, or would have to break something during repair.
It is old, from 2008, I paid $4 new at a store closure sale...and I expect the repair may have cost me $2 to replace a 30 cent thermostat.
It still steams, I use it sometimes when I feel like, but the new iron was like $5, and it works okay.