How to start with repairing project Wurlitzer 2410S

Hi,

I am new to jukebox world. I just bought Wurlitzer 2410s jukebox in non-working condition. It is not powering up. I have the service manual.
The question is - how to start investigate what the problem is? What is your typical steps?

What tools I need to have to diagnose malfunctions, wires, etc?

I know it sounds like total newbie, and it is true - but I will learn quick

Location: Mercer Island, WA

Thanks for your help!

No obvious power to anything? (completely void of power) First thing to check are fuses.

For testing power, you'd have to have some knowledge (as you are dealing with high voltages), but you would need a good multimeter to check that you have 120v to the transformer and the correct voltages (indicated in manual?) coming out from the transformer. Could involve tracing power to the other components after that, if the correct voltages are present at the transformer.

Tim

Thanks! That's exactly what I need for the start.

First rule for machines that have been stored: DO NOT PLUG IT IN!

The amp's high voltage should NOT be applied till it has been recapped. Failure to do so can destroy the main power tran. On Wurlitzers the amp and power supply for the mechanism are integrated. If there is a 5U4 tube for the amp it can be removed to allow the low voltage circuits to be powered during restoration. On the later stereo amps the high voltage is provided by selenium rectifiers so there is no easy way for those unfamiliar with these circuits to disable those voltages, so it is best to await an amp rebuild.

My approach:

1) Look for obvious signs of major failure such as soot above amp transformers or signs of dripping from same. Look for burned resistor and --check fuses for correct types and rating--.

2) look for broken-missing mechanism parts.

I remove the mech, speakers and ballasts along with any other items that can easilty be taken out. I wash the entire cabinet.

I break down the mechanism:

Remove the upper section (the arch with the T-T). That involved four bolts, Approx 4 plugs and a steel cable linkage.


Remove the pin memory unit; Three bolts and several plugs. Be sure to mark the plugs that come from the keyboard to the memory as the original Brady numbers may now be missing.

Remove the mechanism motor.

I wash all items with a diluted floor stripper such as Zep taking care to keep water out of transformers as much as possible. Rinse with hot water and blow dry. I have an 1980s Electrolux vac that i use only for drying equipment.

I f you don't have a service manual, order one from either Always jukin' or Victory Glass. If you have worked on other Wurlitzers from this era and have doc's those will probably be adequate here too.

You'll need to decide if rebuilding the amp is for you, or if it is better to send it out.

A schematic is here: http://www.verntisdale.com/Wurlitzerschem.htm this same person offers packaged kits of capacitors and tubes for amps.

There is a fair amount more involved, but those are the essentials to get you started.

Joining this group might also be helpful: https://groups.yahoo.com/neo/groups/wurlitzer//info

Rob/NYC

Im also a newbie here with my first Jukebox, with only some electronics skills and computer skills as my background. This is a fantastic forum with some very knowledgable people, possibly the best jukebox knowledge you will find in the world. Be slow and methodical is all I can offer, with patience you will get there!

Also, may be worth seeing what engineers you have locally. You may need them to step in if things get ugly, and they may be able to help you source the parts you need

Psychman,
"Parts source" is easy--read the "informational stickies" posted above !!
Ron Rich

Thanks everybody for the directions how to start.

So I opened the box and detach Power supply and Amplifier. This is how it looks:


Can you please take a look on the photo and say what first thing I should start checking?
Few more thoughts:
-I see soot near Amp tubes, but tubes looks good. Probably previous owner change it.
-Huge tube on the Power supply looks blown inside. Big black spot inside on the top. Probably I should start here.
-There were two power inputs (power plugs) into jukebox. One is going directly to the Amp, second goes to light ballast. Is that normal?

Thanks for any comments!

The large tube on the separate power supply is the 5U4 rectifier that supplies the B+ (high voltages) for the amp. This tube should be left out till the amp has been rebuilt. the black/silver spot is called a 'getter". During manufacture is it heated by H-F induction to further improve the vacuum. It is not a fault.

The amp needs a good cleaning and the rusty tran looks like it has been exposed to longterm moisture. Keep fingers crossed.

Those printed boards are easy to work on. There is a slight chance that some portions may have become carbonized and defective, but I suggest you just go ahead with cleaning and capacitor replacement. I have never run into that problem on Wurlitzer boards of that era but I do believe unpopulated reproductions are available if necessary.

If you have basic soldering skills and simple tools like a DVM you should be able to rebuild this amp easily. The 6973 tubes are prone to internal shorts and they can take out a transformer, but since Wurlitzer used cathode bias the cathode resistor will have taken most of the hit.

Rob/NYC

Finally rainy day comes and I found a time to come back to my restoration project.
So I ordered WURLITZER 538 STEREO amp cap kit, but when I take a look on the washed amp label surprisingly I found out it is a 534 model! You can see label in my previous attached pic on the right top.

Can you please help me understand:

1. How it can happened that Wurlitzer 2410S model has 534 amp? It looks original... The only thing comes to my mind that previous owner changed amps from 538 to 534.
2. How different capacitors in 534 comparing to 538?
3. Does it make any sense to rebuilt 534 amp for Wurlitzer 2410S? Will it work anyway?
4. One of the 6973 tubes broken, and I found 6LJ8 tube in box - looks like previous owner bought it as a replacement for 6973. Will it work or I need original 6973 (or cheaper 6cz5)?

Thanks a lot!

Well, that took a while.

-The 6LJ8 is not remotely useable here. Forget it. It is an American version of a dual section European tube.

-The amp should be fine there. The only difference (that I recall) was that the 2300 series amps still used a 5U4 in the PSU and the 2400 series went to diodes. Since you have the correct PSU, all that matters are the mute-squelch plug mating -they should. I do not recall any other differences. In summer 1986 I bought 9 various Wurlitzers . All were the 2300 and 2400 series. They came straight from a warehouse and many were missing parts. We just rummaged around for what looked approximately right and I made them work. The 534 and 538 along with two 532 (mono) amps went into those machines -whether they liked it, or not

Rob/NYC

Hi Rob,
I am SURE, that those phono's appreciated, ANY amp being installed--they probably looked at you as their "life-saver"
Ron Rich

Well, it takes a while to have a rainy day in Seattle
So the good news is I can use this 534 amp with Wurlitzer 2410s. Looks like PSU is also from 2300, it has 5U4 as you mention.
Sounds like it will work with 2410s, right?

Thanks a lot!!

It shood/otta !
Ron Rich

Nice. I'll exchange 538 capacitor kit to 534 kit and will keep you posted.

So after capacitors replacement - what are the next steps? Trace power to tran? How to understand the amp and PCU working good?

Thanks!