Heat and Cold

[nyjb]

Hey,

It's freezing in New York, and that got me thinking.

Does anyone have some insight into the effects of heat and cold on a jukebox's operation?  (Other than the normal effects of tubes getting warm, etc.)  I know humidity and salt effect a box over time; i'm wondering more about operation.

My box can get pretty cold, and I wonder whether there could be danger or other quirks from operating it before it thaws.

Thanks,

Terry

[Ron Rich]

Terry,
It never gets too cold here, but I have been told in the long ago, that "electronics" do not like to be powered up wen "frozen"--best to allow it to heat up naturally to "room temp", first-- Ron Rich

[robnyc]

These machines are designed for commercial service. In many cases they are left in unheated locations while the business is closed. Hideaways are often in basements which can get frigid.

If the environment is severely cold and/or humid it is best to leave it powered so that the internal heat keeps the humidity to a non-dangerous level.

Computerized devices are more sensitive, those can develop temporary 'quirks" -or even refuse to work if the environs are too extreme.

Some of the older transistorized PA and juke maps had little/no automatic bias control on the outputs and gross crossover distortion can occur if they operate in a very cold environment. This was why many manufacturers spec'd a higher-than-necessary idle bias on this amps.

Years ago, op's often left the service light in hideaways powered during really cold weather. The main point here was to prevent the oil in the mech from becoming too viscous and causing the speed to run slow. Unfortunately, they often used too high a wattage for that bulb and often left scorch marks near the light.

Bottom line: If it is an old machine it will probably be OK IF the humidity does not become excessive. If a newer computerized model is it best to leave it powered during the really extreme weather such as what we are experiencing here in NYC.

RobNYC

[e093116]

I've found the cold has helped identify areas where the mech might not be properly lubricated!

On an LS1, when cold it would "throw" the first record after sitting overnight.  I found the levers behind the pickup cradle were "sticky".  Works good now even when cold after disassembly, cleaning, etc.

On a different LS1, I've noticed that for the first couple songs the pickup will not move all the way to the edge of the record (the song starts to play ~3 seconds into the record)...this goes away after about 3 songs and I haven't tried to investigate it yet.

I've also had a couple UPDU6's not pull in the relay for the keyboard after a coin drop or two when cold.  I've cleaned and lubricated those to try to fix the problem with not much improvement.  Generally, on the 2nd or 3rd attempt, it will work, and work fine after that.

The temperatures when these problems occur are in the 35F to 45F range.  I keep the detached shop and house garage heated/above freezing.

I've also noticed what sounds like "slow play" for ~10 seconds or so when playing that first record when the phonographs are "cold soaked" to ~40F or so...

It's supposed to warm up to 30F by Sunday, I'm looking forward to getting the house garage to "room temperature", blasting some records, and grilling that thick ribeye that's been in the freezer.

Bill

[Ron Rich]

Hi Bill,
Slide out the UDPU and look at the lytic cap-- If it's a brown paper 100uf cap, replace it with a 200uf cap, and the PU will probably work when cold-- Ron Rich

[e093116]

Hi Ron,

Thanks for the suggestion, both UPDPs had 200 uF paper caps, I noticed on one of them that the 18 ohm resistor downstream of the cap was "baked" looking, so I replaced both parts last night, but unfortunately I didn't notice any real improvement.  The machine I worked on is closest to the garage door and is probably the "coldest" of all the machines, since the UPDU side of the machine is close to the air leak between the garage door and floor/wall.

I just went out to the garage to see what would happen, the "reworked" guy closest to the garage door worked on the second coin drop, and the machine next to it worked on the first coin drop.  I'll try this same test again tomorrow afternoon after warming up the garage first.

Thanks again for the suggestion.

Bill

[Ron Rich]

Bill,
Are these UDPU-6 Code A, or B? When it fails to operate can you hear the coin coil energize ? Ron Rich

[e093116]

Hi Ron,

The good actor from this morning is a code B.

The bad actor, I can't tell, either there was an incomplete ink stamp for the code letter, or it has worn off over the years.

Both do the same thing when they act up, I can see the add arm move/pulse, but the detent arm (that lifts up to allow the credit wheel to rotate) doesn't move.

If it's of any meaning, the 200 uF paper cap I removed measured around 330 uF, which is one of the reasons I removed it (out of reasonable tolerance).  The replacement measured 207 uF.

I did clean/inspect all of the switches in both units (using a burnishing tool instead of sandpaper!).

Is it possible that a weak pulse from a dirty coin switch could be the culprit?  When I was "testing" the "repaired" unit last night, it didn't initially add credit for several coin drops (though I could hear the UPDU moving/trying for each coin - some coils working), I manually actuated the coin switch and then it started to work.  The coin switch associated with the bad actor is missing the plastic snap on cover, and might be "dirty"?

Thanks as always.

Bill

[Ron Rich]

Hi Bill,
Does the "bad actor" have one, or two fuses ? Are they the correct value ? I suspect that both units have the same problem The credit wheel is sticking to the metal post-- Remove the wheel--clean the post and slide it back on--see if the wheel slides on/off without any problem-if tight, you will need to ream it out--a drill bit, in your hand will work--That 200uf cap is what is supposed to "hold" the leaver long enough for the wheel to spin ---Ron Rich