12-28-2013, 08:39 PM
OK, so....
I checked things for shorts, then saw an unbolted AC wire in the plug, then I spent some timer trying to understand why I am not seeing the resistance when measuring between the plug's prongs while having the switch ON - turned out the switch is oxidized and does not conduct well every time to the meter's voltage, but when subjected to the full AC voltage it obviously conducts well (same story with my 20).
Then checked the tubes, then checked the AC voltages of the transformer, then put the 80 in, checked the DC. One output tube did noty have plate voltage - turned out I need to really insert the speaker plug all the way.
Then I turned the volume on, heard the scratch, heard the hum, then put 6" short piece of wire in and heard plenty of stations and of course my local "good time oldies". Loud and clear.
Now, I have distortion on large volume...well, we'll see.
First I need to align it. DC plates' voltages are within reason, so far did not see the grids but I do not think it is even worth seeing as I have no opens in coils and all resistors are good now.
I will probably take a look just for the heck of it.
The alignment, then we'll see what that distortion is all about, but I have an impression that two reasons may be at play: a speaker (bunch of questions - impedance matching, field coil is weak....) and, well, maybe Ron or Terry or LASJHawk could tell me if the detector solutions in 90 are known to be not so great.....at least in 20 they are.
Oh...and maybe the speaker in the open cone down on a piece of cardboard on the table has something to do with it.
It is playing "All you need is love" now.
Anyways, good end of the day, she's singing, ladies and gentlemen, and this is worth a shot of that Lagavulin now.
PS. Yes. Put the speaker on its side - it sounds...great!
I've just earned the second shot.
I checked things for shorts, then saw an unbolted AC wire in the plug, then I spent some timer trying to understand why I am not seeing the resistance when measuring between the plug's prongs while having the switch ON - turned out the switch is oxidized and does not conduct well every time to the meter's voltage, but when subjected to the full AC voltage it obviously conducts well (same story with my 20).
Then checked the tubes, then checked the AC voltages of the transformer, then put the 80 in, checked the DC. One output tube did noty have plate voltage - turned out I need to really insert the speaker plug all the way.
Then I turned the volume on, heard the scratch, heard the hum, then put 6" short piece of wire in and heard plenty of stations and of course my local "good time oldies". Loud and clear.
Now, I have distortion on large volume...well, we'll see.
First I need to align it. DC plates' voltages are within reason, so far did not see the grids but I do not think it is even worth seeing as I have no opens in coils and all resistors are good now.
I will probably take a look just for the heck of it.
The alignment, then we'll see what that distortion is all about, but I have an impression that two reasons may be at play: a speaker (bunch of questions - impedance matching, field coil is weak....) and, well, maybe Ron or Terry or LASJHawk could tell me if the detector solutions in 90 are known to be not so great.....at least in 20 they are.
Oh...and maybe the speaker in the open cone down on a piece of cardboard on the table has something to do with it.
It is playing "All you need is love" now.
Anyways, good end of the day, she's singing, ladies and gentlemen, and this is worth a shot of that Lagavulin now.
PS. Yes. Put the speaker on its side - it sounds...great!
I've just earned the second shot.