1963 Juke Box resto.

[Gary Mattis]

This Whirlitzer 2710 model made back in 1963 has a 6973 Stereo power amp in it , it sounds good but it needs a rebuild. My question is did Whirlitzer build there own amps ? or did they use Dynaco amps ?. It has a chassis with 2 bread boards in the middle. Also there is a giant 50 volt 120-150 MFD cap under the turn table that cost 51 dollars - a 74808 Cornell Duebler capacitor that I do not see any polarity marked on ? . Is changing this cap critical when it only works for just a few seconds at a time ? . This is my first juke box restoration so any advice or experience you may have is welcome. I had a hell of a time adjusting the record player because of thicker and thiner 45s , it has to be adjusted for playing both.

 

[Shadowdog]

I do believe they built their own amps and why is a 50 Volt cap so pricey? Maybe regular Panasonic or Nichicon would do for much less $. Maybe it's a Motor Run cap?

 

[Gary Mattis]

I think it is a motor run cap , has 24 volts. The juke box parts sellers are total rip offs, everything cost a small fortune, I can see right now I need to avoid them if at all possible
.

 

[larryderouin]

If it's a standard cap, gut the case for the original and stuff it with a new electrolytic. You can get motor Run / start caps at electrical supply houses for fairly cheap (<$15.00).

Got a pic of the cap??? and / or the section of the schematic???

 

[KentTeffeteller]

I think it is a motor run cap , has 24 volts. The juke box parts sellers are total rip offs, everything cost a small fortune, I can see right now I need to avoid them if at all possible
.

In some cases, you may have to buy things from them. Remember that these machines were very expensive new (this cost around $799 new). Mechanism and cosmetic parts, and some other parts are sometimes specific. Wurlitzer built that amplifier. And the selection system and the record mechanism. In that era, that was equivalent to buying a new McIntosh power amplifier and preamplifier, or power amplifier and preamplifier-tuner brand new. Be mindful of that.

 

[ggregg]

When I was rebuilding jukes, I was buying cap kits on ebay. They weren't ridiculously expensive and you got all the right ones. I rebuild the amp in this model. It has a very screwy stereo circuit using a woofer and tweeter on one channel and a full range on the other.

Since this is your first, you may have already been warned about this or not, but do not take the easy route and lock the latch selenoid for free play. Check to make sure it hasn't been done already either. Either run the coin mechanism as normal or tie a button into the coin sensor. Push the button, the machine thinks a coin dropped. Locking the latch selenoid makes it severely overheat and is a big fire risk.

 

[Gary Mattis]

When I was rebuilding jukes, I was buying cap kits on ebay. They weren't ridiculously expensive and you got all the right ones. I rebuild the amp in this model. It has a very screwy stereo circuit using a woofer and tweeter on one channel and a full range on the other.

Since this is your first, you may have already been warned about this or not, but do not take the easy route and lock the latch selenoid for free play. Check to make sure it hasn't been done already either. Either run the coin mechanism as normal or tie a button into the coin sensor. Push the button, the machine thinks a coin dropped. Locking the latch selenoid makes it severely overheat and is a big fire risk.

I would like to hear more about the change box button ? , I have a button on the solenoid behind the tone arm to change the records , push once after selection and it loads, push a second time it plays, shuts off automatically, not the best set up but it works, can I make it work automatically ?, second question ? I have the 545b amp with the green Brit caps on V2 the 12AU7 , C3 , is that cap polar or non polar ?

 

[ggregg]

Never messed with the mechanism on mine, other than to change the belts. It worked fine. Plus it's long gone. Don't remember, sorry.

The change box button will work if you have a working coin box mechanism. There are slots that the coins go through before they get to the coin box. On those slots is a lever sensor attached to the control box. This advances the plays when the lever is moved. By attaching a spring switch to it, you can make it do the same thing as moving the lever (closing the switch temporarily). Which makes the control box think a coin has dropped and turns on the latch solenoid to move the record count. On mine, I just used the same quarter over and over and left the coin box door off.

 

[toxcrusadr]

Any brand names on the tubes themselves? That may give some clue as to who made the amp. But Wurlitzer also made organs, and I suspect they made their own amps and such just because they were so big in the industry.

 

[ggregg]

All the brands made their own amps and used a proprietary mechanism until the CD versions came out in the eighties.

 

[Gary Mattis]

Never messed with the mechanism on mine, other than to change the belts. It worked fine. Plus it's long gone. Don't remember, sorry.

The change box button will work if you have a working coin box mechanism. There are slots that the coins go through before they get to the coin box. On those slots is a lever sensor attached to the control box. This advances the plays when the lever is moved. By attaching a spring switch to it, you can make it do the same thing as moving the lever (closing the switch temporarily). Which makes the control box think a coin has dropped and turns on the latch solenoid to move the record count. On mine, I just used the same quarter over and over and left the coin box door off.

What is the easy rout lock latch solenoid that may or may not have been done, how do I know if someone did that already or not ? I saw 2 white wires stripped back on the change box mechanism, but they are disconnected from each other now, looks like they may have been connected before to eachother or something else ? , I understand where to put the switch at where the coin drop sensor is at the plastic coin switch.

 

[ggregg]

If the unit is in free play, need to figure out what they did to get it to do so. It's been a number of years since I worked on mine but with a service manual, it's pretty easy to figure out.

 

[nasadowsk]

If you hear the machine humming all the time from the keyboard area, or the 'select' light is always on, that's generally a hint that someone screwed with the credit circuits.

Honestly, if the coin switches and rejector are all that are missing, I'd try to chase them down from somewhere. Half the fun is dropping in a coin to listen

That Wurlitzer mech is pretty decent. The earlier ones where it was visible are neat, because you can watch it play records. But you've got the stereo setup, which blows the Cobra system that they used for so long out of the water. Trouble is, everyone used 6973s in their stereo amps...

I like AMI's better. They had a better sound system, even the mono ones. The F and G and a few others had what amounted to Williamson amps, with GE VR cartridges, and horn loaded speaker systems. They're quite nice! Seeburgs are fun too, if you can get the Tormat to work. Rock-Olas? Never heard one I liked. They all sound like crap, IMHO.

 

[toxcrusadr]

6973s do show up in BT now and then. I've bought a bunch for my Ampex monoblocks and decided to stop collecting them. Not terribly easy to find or cheap, but they're out there.

 

[ggregg]

That Wurlitzer actually is the same mech as the open one, it's just covered up. Mine was actually a newer 2900 (with a 2700 amp) and they exposed it again for the last time for a few years. It is a good mechanism, lots of moving parts but reliable. Mine actually sounded quite good, ceramic cartridge, weird speakers, and all.

Certain AMI's do sound nice as do quite a few Seeburgs. The tormat was the most reliable part of the Seeburg mechanism. Other than the connecting wires sometimes breaking, they were stone cold reliable and got rid of about a gazillion moving parts that pin banks have. The problem with Seeburg mechs is the awful white grease they lubed them with. Jams up the clutch something awful eventually. A good degrease and relube, is all many a Seeburg mechanism needs to get it going again. The worst part is finding needes for the older Pickering magnetic cartridges. They are quite expensive and getting harder to come by all the time. The later sixties and newer ones are much easier to find. The best sounding juke I ever had was a Seeburg LS2 from 1968. Nothing special and not worth much but sounded really good. Seeburg's first sealed speaker set up and it really made a difference.

 

[Gary Mattis]

If you hear the machine humming all the time from the keyboard area, or the 'select' light is always on, that's generally a hint that someone screwed with the credit circuits.

Honestly, if the coin switches and rejector are all that are missing, I'd try to chase them down from somewhere. Half the fun is dropping in a coin to listen

That Wurlitzer mech is pretty decent. The earlier ones where it was visible are neat, because you can watch it play records. But you've got the stereo setup, which blows the Cobra system that they used for so long out of the water. Trouble is, everyone used 6973s in their stereo amps...

I like AMI's better. They had a better sound system, even the mono ones. The F and G and a few others had what amounted to Williamson amps, with GE VR cartridges, and horn loaded speaker systems. They're quite nice! Seeburgs are fun too, if you can get the Tormat to work. Rock-Olas? Never heard one I liked. They all sound like crap, IMHO.

Nothing is missing with the coin slot mechanism , its all there still but it selects without a coin so someone did something, the coin lock box is gone and the coin drops into a open box on the side. I just rebuilt the amp and it humms loud as hell in the play mode, not sure what's causing that unless those cathode by pass caps have to be non polar ? I put regular polarity ones in , the amp did not humm like that before the rebuild. So it must be something that I did making it noisey, it does play and does work, just not right now, when the brush goes over the tone arm it quiets down and has a normal idle, in the play mode the humm gets real loud, I was thinking maybe those two Sprague paper in oil caps underneath are not e caps ?, The cathode by pass caps had red positive and black negative rubber ends when I cleaned them off , so I think they are OK, the two Sprague caps I thought were e caps may not be ecaps ? See the pictures attached. I agree on making the coin work again , it is part of the thrill !, School days by Chuck Berry needs to be in there too where he say; drop the coin right into the slot, you gotta hear something that's really hot ! , I just checked it and the select light stays on all the time. I switched a ground on a e cap and the humm went away sounded great for a minnute but then the cap blew, wrong ground I think ,made some kind of a mistake changing one of the e caps, will look at SKU tomorrow and try to figure it out. Too tired now, took a long time to rebuild this one. , I Hate working on PC boards.

 

[ggregg]

Those don't look like e-caps to me. Just big paper caps.

 

[toxcrusadr]

Yep, wax coated paper foil caps. I'd replace them.

I don't know that I'd trust those rubber ended bypass caps, at this age. Pennies to replace them and then you know.

If you replace all the caps and you still have a hum, and everything is correct, watch for lead dress/wire routing. Esp. if you put in any new wires or a terminal strip to mount caps. Usually more of a problem in radios but just something to be aware of.

Just FYI, some old caps had one lead marked as 'outside foil' and that was usually the end you connected to ground, which provided some shielding against interference. Had nothing to do with electrolytic or not and in fact those were usually nonpolar film caps.

 

[Gary Mattis]

Got the amp rebuilt and back in , it sounds good, I made a ground mistake last night and blew a new e cap, it had a 100@250 in it and all I had was a 100@160 but it works, next time I order parts I will get the right one for it. The tubes are short Grey plates on the pre amp, I have some long grey plate 12AX7's and some RCA long black plate 12AU7's , gonna put those in after it cools down, the output tubes are mixed up pairs, 2 GE and 2 RCA, I guess I will have to bite the bullet and get 2 more matched RCA's for it. May as well get 2 RCA black plate 12AX7 tubes for the pre amp while I am at it !, Ordered a hard copy service Manuel for it, want to fix the select light problem because it is staying on.

 

[Gary Mattis]

Yep, wax coated paper foil caps. I'd replace them.

I don't know that I'd trust those rubber ended bypass caps, at this age. Pennies to replace them and then you know.

If you replace all the caps and you still have a hum, and everything is correct, watch for lead dress/wire routing. Esp. if you put in any new wires or a terminal strip to mount caps. Usually more of a problem in radios but just something to be aware of.

Just FYI, some old caps had one lead marked as 'outside foil' and that was usually the end you connected to ground, which provided some shielding against interference. Had nothing to do with electrolytic or not and in fact those were usually nonpolar film caps.

I put e caps there because it said MFD and both went to ground on the pre amp board ? , and they are working , I ordered a hard copy service Manuel last night for it , one that comes with a SKU. The line on those caps went to ground, how can I tell other then waiting for the SKU ? Will e caps hurt anything there if they were non polar ?