Realistic Miracord 40A makes loud POP sound at shutoff ??

I like my Miracord 40a turntable, which I have owned and used since around 1970. But........after playing a record, and it completes cycling to replace tonearm on rest, and then "shutting itself off".........there is a loud popping sound sent through the amp (the amplified sound of a switch maybe??). I wish I could eliminate that. I'm not a real savy electronic type, but I am reasonably knowledgeable (I know a capacitor from a resistor.....I think). Has anyone a solution for this problem?
Thanks!

On higher-end turntables they usually employ a capacitor across the power switch to quell the spark made when the switch opens/closes. (also known as a "snubber" capacitor)
This also "quiets" the switch.

Due to the fact this turntable is 40 years old, it probably crapped out, as old caps do.

Try replacing, or jumping the switch terminals with a new cap rated at 600 volts/0.047uf, and let us know how you make out.

Thanks for the suggestion about the "snubber capacitor"......I could see it wired across the switch, and I speculated that it might act to delay or dissipate the effect of opening that switch.....interrupting the power..........but I don't really understand why it would work. I thought maybe it was the kind of thing an electrical engineer might just "know" about mechanical switches........and "know" the solution.

I'm sure you are right that it just slowly "crapped out" after 20 or 25 or 30 years of use (capacitors are not immortal I have learned from my 40 years old amp.....it needed one once). I don't remember when it started this "pop". It totally amazes me that this old stuff still works, and what's more......works really well (given the limitations of the medium itself......grooves cut into "plastic' ...and a little, jiggling, vibrating thing.....I mean, come on now!). Remarkable accomplishment.....kudos to the designers back then.

I'll try a new "snubber". I can read on it exactly what it is.......and will try to find a match.

What does it say n it ? Ron Rich

The "snubber" capacitor on my Miracord 40 A is labeled ERD 500V~ 0.05µf 50 ohms (omega) -25/+85 degrees C F 1435 LV8 - 11095.

I read on Wiki that putting a snubber capacitor across the on/off switch provides a place for current (that was flowing when "on") to go, and thus creating a voltage difference within the capacitor.....when the switch is turned off. This prevents a spark (because of the voltage difference on the two sides of the switch) from jumping (.....and making the "pop" sound..the spark, that is) when the flow of current is abruptly interrupted by opening the switch......or shutting "off".

Very clever indeed.

Now I just have to find out where to get a new capacitor.

As was suggested, a .047/630 volt cap is what you should use--they are available at any GOOD electronics store for a couple of dollars--If you can't find one, contact me off list and I sell you one-- Ron Rich ronnnrich@yahoo.com

yorf1234 wrote:The "snubber" capacitor on my Miracord 40 A is labeled ERD 500V~ 0.05µf 50 ohms (omega) -25/+85 degrees C F 1435 LV8 - 11095.

I read on Wiki that putting a snubber capacitor across the on/off switch provides a place for current (that was flowing when "on") to go, and thus creating a voltage difference within the capacitor.....when the switch is turned off. This prevents a spark (because of the voltage difference on the two sides of the switch) from jumping (.....and making the "pop" sound..the spark, that is) when the flow of current is abruptly interrupted by opening the switch......or shutting "off".

Very clever indeed.

Now I just have to find out where to get a new capacitor.

That capacitor is really a 0.05uf cap with a 50 ohm resistor in series with it.
The use of the resistence is not critical, but it tends to provide a "time constant" to the mix, softening the charge effect on the capacitor.
A plain cap will work just as well, as I mentioned before.

I see. I ordered a similar paper/wax capacitor (old type I guess....)from the TubeStore in Canada.....it's on the way.

Thanks for the idea about resistor in series.

.....still popping.

: (

the new cap did not fix : (

Just a guess--you may have a badly "burned" switch--can you replace it ? Ron Rich

Ron Rich wrote:Just a guess--you may have a badly "burned" switch--can you replace it ? Ron Rich

In most cases, the switch itself can be dis-assembled and the contacts burnished to remove the pitting and carbon deposits, due to sparking.