I've been working on a RCA 9289-B amp.
It's up and running, and it sounds pretty good, I'm impressed.
Like a lot of RCA amps it's got that wonderful selector switch for tube status and B+ voltage.
The last position is supposed to be a VU option.
And the meter itself is just a 1ma meter with a red-green-red scale on its faceplate.
The #1position is off, or NC, then #2 is tube 1, #3 is tube 2 etc etc. Position 8 is B+, and position 9 is VU.
The VU is the ONLY position that I get NO reading on the meter.
The only schematic I have is here https://pacifictv.ca/schematics/rcami9289schematic.pdf
That schematic is for the earlier MI-9289 and NOT the MI-9289-B so I'm not entirely sure it's 100% accurate here but it should be pretty close.
I put a volt meter on the MA meter to see if was getting any signal, and when I switch it from the B+ position #8 to VU position 9 it goes to 300 volts DC.
Can someone give me any clues on what they think is going on? I'm not sure I understand what it's trying to read to get a VU signal here?
It's up and running, and it sounds pretty good, I'm impressed.
Like a lot of RCA amps it's got that wonderful selector switch for tube status and B+ voltage.
The last position is supposed to be a VU option.
And the meter itself is just a 1ma meter with a red-green-red scale on its faceplate.
The #1position is off, or NC, then #2 is tube 1, #3 is tube 2 etc etc. Position 8 is B+, and position 9 is VU.
The VU is the ONLY position that I get NO reading on the meter.
The only schematic I have is here https://pacifictv.ca/schematics/rcami9289schematic.pdf
That schematic is for the earlier MI-9289 and NOT the MI-9289-B so I'm not entirely sure it's 100% accurate here but it should be pretty close.
I put a volt meter on the MA meter to see if was getting any signal, and when I switch it from the B+ position #8 to VU position 9 it goes to 300 volts DC.
Can someone give me any clues on what they think is going on? I'm not sure I understand what it's trying to read to get a VU signal here?
I would check R52.
Also ensure the contact plates have not rotated slightly causing make before break contacting.
Fit a new meter.
Also ensure the contact plates have not rotated slightly causing make before break contacting.
Fit a new meter.