Rowe MM5 jukebox question
Posted: Thu Oct 10, 2013 11:07 pm
I'm new here and have a few questions about a Rowe MM5 jukebox that belongs to my aunt and uncle.
I have an original service manual.
The jukebox has just been restored by me to proper operating condition and when I tested the original tubes they tested very bad and I wound up replacing the 7868 tubes with 7591 tubes after seeing how expensive the 7868 tubes are.
So far everything works great for the most part.
Had to fix the magazine motor as the two pins in the motor that engage a gear were worn. I just disassembled the motor, removed the pins and inserted them to where the worn ends are in the motor rotor.
The annunciator moves, but it has a jerky movement to it and often stops one short of the right indication. There looks to be some slight rust on the drive cable and the metal piece that rides in the plastic bushing. Could the rust on the metal piece that goes in the plastic bushing cause the annunciator to not turn correctly?
Also every once in a while after making a selection with the number and letter buttons the search unit will keep running for about 30 seconds then it will stop, but the selection that plays is wrong. I can then reject the record and it will work right for a random amount of selections (usually more than 10) before having the same problem again.
I still have two 5uF caps in the record mechanism to replace and 1 100uF capacitor in the push button assembly to replace as well.
The speaker crossover caps will also be replaced with metal film capacitors.
One thing I cannot figure out is with the listed impedances of the speakers and the crossover frequency, using online crossover calculators the values of crossover capacitors used (used the value listed on the capacitors 68 uF woofers 22uF tweeters same as the manual says they should be) do not agree with what the calculators say they should be for the given crossover frequency. The parts list indicates a carbon resistor (part # 719-00102 figure 1 index# 92 page 5-12 and 5-13) in series with each midrange/tweeter, but none of the speaker connection diagrams show the resistor at all. What value is it?
I have an original service manual.
The jukebox has just been restored by me to proper operating condition and when I tested the original tubes they tested very bad and I wound up replacing the 7868 tubes with 7591 tubes after seeing how expensive the 7868 tubes are.
So far everything works great for the most part.
Had to fix the magazine motor as the two pins in the motor that engage a gear were worn. I just disassembled the motor, removed the pins and inserted them to where the worn ends are in the motor rotor.
The annunciator moves, but it has a jerky movement to it and often stops one short of the right indication. There looks to be some slight rust on the drive cable and the metal piece that rides in the plastic bushing. Could the rust on the metal piece that goes in the plastic bushing cause the annunciator to not turn correctly?
Also every once in a while after making a selection with the number and letter buttons the search unit will keep running for about 30 seconds then it will stop, but the selection that plays is wrong. I can then reject the record and it will work right for a random amount of selections (usually more than 10) before having the same problem again.
I still have two 5uF caps in the record mechanism to replace and 1 100uF capacitor in the push button assembly to replace as well.
The speaker crossover caps will also be replaced with metal film capacitors.
One thing I cannot figure out is with the listed impedances of the speakers and the crossover frequency, using online crossover calculators the values of crossover capacitors used (used the value listed on the capacitors 68 uF woofers 22uF tweeters same as the manual says they should be) do not agree with what the calculators say they should be for the given crossover frequency. The parts list indicates a carbon resistor (part # 719-00102 figure 1 index# 92 page 5-12 and 5-13) in series with each midrange/tweeter, but none of the speaker connection diagrams show the resistor at all. What value is it?