DS160 Sound

Darrell,
What do the voltages read--I doubt both output transformers are bad ?
Ron Rich

Ron

I hooked the black probe up to the 25 - OHM resistor found in the electrolytic condenser and the red probe to pin 9 of 6973 tubes. I get 110, 85.5, 107 and 86.7 ohms, which should indicate that both audio transformers are OK.

I placed the probes on each leg of the 100 ohm resistor and do not get any reading at all. I have heard you can not check a resistor in circuit. If you can in fact check a resistor in circuit and I did it the proper way, I may have found the problem, the 100 ohm 7 watt resistor is open.

Does this make sense?

Best
Darrell

Darrell, you have likely found the problem.

The one caveat is that residual charge on the caps can confuse the readings so at this point I'd just confirm it by disconnecting one lead from that resistor and measuring again.

This is probably yet another causality of Seeburg's omission of proper fusing, however, measure to ground from each tab on the caps to check for shorts and meter the rise of HV when you power it up again. There is always the possibility that a filter shorts when voltage is applied.

Rob.

Darrell,
Be careful--reading resistors ( and other components) in circuit is always "iffy". A lot will depend o the meter used, and the circuit the component is in. An open resistor will always read just that--one that has drifted, may read out of spec., or one that is good may read out of spec., due to the other items in that circuit. One caution, when checking in the power supply region, is that if that resistor is being used as a bleeder (to ground), and it's "open", there most likely is high voltage on the cap side-even with the power off for years ! So--follow the old rule, (BEFORE "cutting", or "removing" it) and using one hand ONLY (other hand in your pants pocket), take a jumper wire and connect it to the ground side of the suspect resistor, and the other end, of the jumper, to a known good resistor. Then connect another jumper to the other end of the good one, and lastly to the "hot" side of the suspected bad one.
Ron Rich

Rob & Ron

Cut one leg and there is no doubt that the wire wound 100 ohm 7 W resistor has failed. Ordered some from mouser as no place around here has them.

Thanks for the tips, will let board know results when I recieve and get new resistor soldered in.

Best
Darrell

Ron/Rob/Mark

Replaced 7 Watt 100 - ohm resistor (R129 on schematic) and life is good again

Many thanks for all who offered their help, it is greatly appreciated.

Best
Darrell

Hi All

Guess what, I now have a DS100 that continues to lose all sound. Turning the phono off & on normally results in a dull roar and pop and restores the sound for various amounts of time before it fades out to nothing again.

I have went through all the tubes & replace 2 that checkes bad or weak, 5u4 & 6973. Checked 100 OHM 7 watt resistor & it checks OK.

I assume the next step would be o check the filter caps, is that correct?

Best
Darrell

Darrell,
Not necessarily--probably time to remove that amp, pack it up and ship it, along with one of those "coffee cans" you havefull of $$, buried in your back yard, to a pro--before you burn something up that costs you three, or four, of those coffee cans --
Ron Rich

Indeed, a 7 watt wirewound resistor going bad?
It'll certainly be something causing such a failure.
Replacing it and not thoroughly going over the chassis will wind up as mentioned - dead again.

Voltages, idle currents, bias levels - ALL need to be monitored and compared to the rated values.
"Service Manual" and "troubleshooting" time.

Perhaps the board does not realize that this thread has dealt with three different Seeburg DS Jukeboxes with sound problems. The first two were resolved with the replacement of the 7 Watt wire wound resistors. That was over 9 months ago and both Jukeboxes are playing great with no further signs of any problems. I also placed an additional fuse in all 4 boxes to protect them as the board urged.

The third one I may have just saved myself a coffee can or two . I tried 2 different 5u4 tubes with 5 pins with no change in the problem. I then tried a 5u4 tube with all 8 pins present. The problem has now disappeared and the sound is fine, it no longer fades out and the pop and rumble is now gone when you turn the phono off. A friend suggested that the socket may have been bad and a tube with all the pins present supports the tube for better contact of the 5 pins, if that makes any sense to you?

Best
Darrell

Since the loss of sound and amp rumble/pop to restore sound returned. I removed this amp and placed it in a unit that did not have any known problems (been playing over one hour with no prolems), so I believe the problem is not in the amp that was rebuilt in May of 2004.

The amp that was working great I then placed in the unit that is having the sound problems and sure enough this good amp now has the same problem as the amp I took out.

It seems apparent that the problem lies somewhere else. Suggestions on how to proceed form here would be appreciated

Best
Darrell

Darrell,
Does this happen on both record sides ?
Motor "rubber parts" ? Thrust bearing lubrication/ adjustments ?
Ron Rich

Hi Ron

Turned unit on to check B sides. An A side was playing and when I selcted a B side the sound returned when I pushed the selector buttons, there was a roar sound and the sound returned. When the B side was playing the sound went away and I again used the selector keys and once again while making selections the sound came back. Unfortunately the sound then goes away again.

So, yes the problem exists on both the A and B sides.

When the sound is present it does not sound like the "rubber motor" parts, I have replaced those on two other machines and have an idea what that noise sounds like when the rubber parts are bad.

Thust bearing lubrrcation and adjustment may be a problem, U was not aware that that came into play with the sound.

I also think I wil start at the speaker wires and work backwards. Someone has rigged the ear speakers to work without the TASU being plugged in. They also altered the wires that would plug into an SHFA5 amp and the amp in the unit is a SHFA4 that does not have a place to plug in the wires.

Best
Darrell

Darrell, when the sound goes away, have you tried removing the mute plug?

Try running the phono that way and see what happens, the sound will be overly loud and probably a bit distorted but we are looking for faults in the mute-squelch wiring in the mech.

Rob/NYC

Evening Rob

When I pilled the mute plug the sound returned nice and loud, then after awhile it started fade. When I would tap on the prongs of the mute switch, touch the mute plug against the case and/or move the plug around the sound would return.

I suppose I should now check the mute switches for pitting/adjustment and possibly inspect mute plug wiring?

Best
Darrell