Jackk
01-30-2011, 09:26 AM
My X1000R it wouldn't play, it would start and stop almost immediately. What had happened is that the diode feeding the play and brake solenoid had gotten so hot it made a cold solder joint. The instant start and stop I saw was from a "boost" that the solenoids (sol) get from another power source to engage. I fixed that solder joint and even though the diode wasn't bad, I replaced it with a 3 amp diode. This 3 amp diode still runs hot. The two brake sol are wired in series and take about 0.5 amps. The play sol takes about 0.6 amps. Together they take about 1.2 amps which seems more that the stock 1 amp diode should be asked to supply. This is diode D44. If you are looking at the rear of the deck, it is located on the Control PCB which is next to the RCA jacks. The diode is at the corner of the board next to a wire that is directly soldered to the board. Looking at the top of the board it is left of all the large transistors.
The purpose of D44 is to block the higher “engage” voltage which comes on for a moment to help pull up the solenoids.
I assume that the sol should draw about half an amp as it seems hard to believe they would all fail at the same time. Plus the deck seems to work fine. So now I have a 1 amp diode supplying 1 amp, which seems like a poor design.
I’ve tried swaping D44 with another diode from the deck and it got hot as well. I also replaced the two filter caps for the 15V supply and that didn’t help.
I have a friend who has one of these machines and I measured his voltages and currents. His numbers were the same as mine, but his diode doesn’t get hot. My solenoid does get warm.
Everything was almost exactly the same as mine. 1.4 amps through D44.
My Machine: D44 tape stopped 18.2V, tape on 15.2V Diode drop .8V, ground to diode ac .86V
His Machine: D44 tape stopped 18. V, tape on 15.4 Diode drop .8V ground to diode ac .77V
I know someone else who had this problem and never was able to fix it. I would guess we will see it again, so it might be handy to know what a good deck reads before the problem starts.
I wonder what the DC resistance of the solenoid should be? Are the currents I’m seeing normal?
The purpose of D44 is to block the higher “engage” voltage which comes on for a moment to help pull up the solenoids.
I assume that the sol should draw about half an amp as it seems hard to believe they would all fail at the same time. Plus the deck seems to work fine. So now I have a 1 amp diode supplying 1 amp, which seems like a poor design.
I’ve tried swaping D44 with another diode from the deck and it got hot as well. I also replaced the two filter caps for the 15V supply and that didn’t help.
I have a friend who has one of these machines and I measured his voltages and currents. His numbers were the same as mine, but his diode doesn’t get hot. My solenoid does get warm.
Everything was almost exactly the same as mine. 1.4 amps through D44.
My Machine: D44 tape stopped 18.2V, tape on 15.2V Diode drop .8V, ground to diode ac .86V
His Machine: D44 tape stopped 18. V, tape on 15.4 Diode drop .8V ground to diode ac .77V
I know someone else who had this problem and never was able to fix it. I would guess we will see it again, so it might be handy to know what a good deck reads before the problem starts.
I wonder what the DC resistance of the solenoid should be? Are the currents I’m seeing normal?