SEEBURG 100 R POPPING THRU SPEAKERS

I HAVE A SEEBURG HF100R THAT IS DRIVING ME CRAZY! WHEN PLAYING I GET A STRONG POP THRU THE SPEAKERS. DOES NOT HAPPEN ALL THE TIME , NO SPECIFIC PATTERN. I HAVE BEEN THRU THIS MACHINE SEVERAL TIMES AND STILL CANNOT SOLVE THIS ISSUE.

THE AMP HAS BEEN REBUILT AND EVEN SWAPPED OUT WITH AN AMP FROM ANOTHER MACHINE WITH NO SUCCESS. ALL COMPONENTS HAVE BEEN REBUILT, CLEANED AND ADJUSTED. DOES ANYONE HAVE ANY SUGGESTIONS. THANKS!

A few questions:

-Does it happen at random times? that is, only when a record is mounted and playing, or can it also happen during scan as well.

-When you swapped amps, were -all- of the tubes swapped as well? Tubes with a loose element that are trending toward shorting can cause this problem. It becomes dangerous in the case of output tubes as they can take out an output transformer.

-Try removing the mute-squelch plug from the amp and see what happens. It is remotely possible that current is getting into the mute ckt via the switch stacks in the mech. I've not seen this happen, but since I can't actually see the machine, we have to try a few additional possibilities.

-Remove the 6SK7 (AGC) tube and see what (aside from a level increase) happens.

Rob-NYC

As Rob wrote--
Need to know WHEN this happens ??
Ron Rich

First thanks for the input on my HF100R problem. The popping noise is only when a record is playing. I tried exchanging and testing the tubes without any success. I took an amp from a 100J that was playing fine with its own tubes and put it in the R and the popping was still there. I have not tried removing the mute plug or the 6SK7 tube but will try those suggestions. I am pretty sure this is not a tube issue. Thanks again for your help and I will keep you updated. The Record Machine

Just to update everyone I have tried pulling the mute plug and then the 6SK7 tube and the popping is still present. Any other ideas? Thanks.

The problems can be anywhere.
A tube could have an intermittent short.
A resistor could be intermittently open.
The list goes on.......
But to diagnose something such as this over the internet is in my opinion, a waste of time.
Even the finest techs cannot give solutions from afar over a screen.
The best solution is to have an experienced tech go over the unit to do a hands-on diagnosis.

Do you have a meter ? If so, measure the ring of the RCA input plug ( remove it from the amp first), to all grounds--chassis of the amp--mechanism itself and WSR--It should be open ! Also, check the tip of that plug the same way . Which cartridge is installed in that phono--and, has the correct retaining screw been used ?
Ron Rich

Ron,
Thanks for the reply. I can tell you that the cartridge is a Pickering 345D and the screws that mount it to the tonearm are not original. I believe that the replacement screws are longer than the originals as I can see the tail end of the screws slightly recessed in on the back side of the tonearm. I also know that the original RCA plug was replaced with a newer version. I have not yet had a chance to check the RCA plug with a meter. Recordmachine 183

I can tell you that the cartridge is a Pickering 345D

OK, now I know the problem. Static electricity is building up due to friction of stylus and record. This happens at times right after I install a new stylus. After a period of use this stops happening. I suspect that it has to do with ambient dirt and oil forming a conductive path to the cart shell. New, or freshly washed vinyl records hold charge more readily then the reground plastic.

The shell of the cart is supposed to be grounded but Pickering's "quality control" was crap for these low-end carts and the split-shell design made for this sort of problem.

I opened one of the NOS 345-03d retro cart tubes I have here. One side of the shell shows 54 ohms to one pin -the other side is totally floating. Another one has both side showing 3.4 ohms to one pin. I'm sure if I test the other five here I'll find similar variations.

Try this: Do an ohmmeter test from the shell of the RCA pickup plug (remove it from the amp) and the cart shell. If the reading shows low resistance to the center pin of the RCA plug that means that the cart shell is on the 'high" side of the signal line. Reverse the wires at the terminal strip on the pickup assembly so as to put the cart shell and RCA shell in continuity. That should reduce-eliminate the problem. If there is high resistance, or open from cart shell to the RCA shell, the cart was poorly constructed and all you can do is use the machine and, as I mentioned, after a while the problem will go away.

In my commercial locations I just ignore this and it eventually stops.

I wish you luck and patience.

Rob/NYC

Hey Rob,
You were right!!!! I reversed the wires and that solved the problem. I never thought it could be the cartridge as I use them in all the Seeburg's I refurbish or restore. Many thanks and all the best. The Record Machine