ESX100 Problems

[paullperth]

Hi,

I am a new here and am just starting my first jukebox resurrection. It is an ESX100 Marauder, 235v/50hz unit. While this is my first jukebox, I have restored and repaired a variety of record players and tape recorders so I am not a complete novice. Certainly not an expert though!

The machine is showing the scan twice and do nothing thing but before I can even think about looking at the cause, I need to sort the power.

I had to replace the power transformer in the SCC9 unit as it got extremely hot under no load. I got a replacement via Jukebox Revival in the Netherlands and all seemed well. However I am not getting the right voltages at the test points. I get 27.5v at the 27v test point, 198v at the Hi V point (schematic says 235vDC/150v with stepper connected” and 0 at Write in Source.

What could be going on? I have checked every component against the schematic and replaced leaky caps and out of tolerance resistors. I am getting the correct 24vAC and 40vDC feeds. Is there supposed to be a constant 395v at test point 2?

The new transformer has 140vAC, 26vAC and 30vAC secondaries. No idea what the original spec was because the old transformer was not functioning correctly. I was getting 15v on the “red” secondary which is 140v on the replacement.

I’d really appreciate a little nudging in the right direction as to possible solutions.

Thanks

Paul

[jukenorman]

Hi Paul,

I have very limited documentation on your jukebox but I can help you a little bit. I don't have the diagram for the SCC9 but I do have the SCC6 diagram which is fairly similar. On my SCC6 diagram, somebody (not me) has scribbled 140V on that secondary winding so that looks right (and double checks if you do the calculation). The DC is a voltage doubler circuit so check the diodes and electrolytics and yes, you should be getting 395VDC at the 1/8A fuse.

Also if you pull the fuse and you are reading 395V at the "hot" side of the fuse, then something further down the line is pulling down the voltage.

Norman.

[paullperth]

Hi Norman

Thanks for the info. Not sure if I can post the schematic here?

I have 388v at the 1/8 fuse. When the machine is scanning I can see varying voltages across the Read Out teat point. I have nothing at the Write In test point. I have put an analogue and digital meter there and can see a brief spike when I make a selection, but nothing like +395v.

Because I don’t know the history of this machine including when it last played a record, I am relying on getting the amp and power supply right so that I can then move onto the actual mechanics.

Tony Miller’s site says:

“First, check the Write-In voltage (usually labeled 'Write-In Source' on the control center or selection receiver test terminal strip). For the digital machines (black/gray or red boxes), the voltage measured at this point will be about +125 VDC. For the solid-state machines, this voltage will be +395 VDC or +150 VDC depending upon model and number of selections”.

I certainly don’t have 395v there and can’t see any obvious way of finding it. The power supply has been rebuilt. Only the thyristor and 4 diodes remain. Everything else has been checked and replaced with like-for-like equivalents.

The machine accepts coins, the select light comes on and I can press the selection keys. The select light then goes out and the machine scans. The counter on the SPU advances 1 each time a selection is made. If I manually trip the mechanism, it will play just fine. It won’t trip automatically at the end of the side and the mute trip is intermittent.

I think I am going to leave it alone for a couple of days and take a look with a fresher pair of eyes. Been at this SCC for a week and am probably missing something obvious. Please let me know if anything strikes you as an obvious line of enquiry. I would really appreciate it.

Paul

[jukenorman]

Hi Paul,
I would be surprised if 388V is not OK, it's less than 2% low! If you remove the fuse and find it's still 388V, there's little you can do other the move the mains transformer taps - if there are any!

I don't know exactly where the test point you are referring to is, it is not shown on the simplified diagrams that I have of your machine. The write-in voltage is 150V although it is derived from the 395V, you will see the 150V zener diode that clamps it on the schematic.

The conventional wisdom for checking these Seeburgs is to start with the read-out and trip functions and ensure they are OK. To that end, you need to refer to the "sticky" above on the battery test and follow it. There is a lot of info already on the forum of how to proceed from there but if in doubt, ask!


Norman.

[paullperth]

Thanks Norman!

I am measuring from the terminal board TB3101 on the front of the SCC9. The schematic references each measurement point as it relates to this board. Tony Miller’s site says that 395v Write In voltage is supposed to be found at points 6&7 which are marked Write in source and Write in load on the front panel. This actually the Write in PULSE voltage, hence my confusion at not finding a constant 395v or similar there.

The point marked +150v in the photo is indicated as Hi V on the schematic and says that it should be 235v DC and 150v with a stepper. I am reading around 200v. As I have no plans to connect a stepper, this does not worry me .

I revisited the voltages after work today and am feeling less pessimistic now, having gone through the simplified write in schematic. I had been reading the main SCC schematic. Our mains voltage fluctuates quite a bit here so that may explain why I am reading 377v today at the 1/8 fuse. This translates to 321v at the write-in cap. This should be more than enough to supply the 150v needed for write in. I think I can close the book on that one.

II wasn’t sure if the trip relay was working. I didn’t hear any clicking nor see any movement. I have cleaned the contacts. However today, when I checked for 27v on the cathode of the thyristor, the relay clicked so I assume it to be working.

I have tried the battery test with no success. I have also tried removing/reinserting the tormat plug while scanning and had no success. I have read that the detent switch, dirty tormat contacts and/or poor grounding can also be suspects. I am quite happy to move onto other troubleshooting processes provided I can eliminate the SCC from my enquiries. I think I now can. I just worry that I will waste a lot of time chasing imaginary rabbits down rabbit holes unless I can be sure that all is well there.

I have Ron Rich’s Seeburg Mechanism Guide and am awaiting delivery of a couple of Tony Miller’s books. I am hoping that these, along with the brilliant people here, will help me sort out this machine

Paul



Edit: photo added

[jukenorman]

Hi Paul,
You need to get the battery test working. Of course, firstly, that relies on the detent switch being clean and properly adjusted. I use an old neon mains panel lamp as a substitute for the Seeburg test lamp (there's a link that can be opened to insert the lamp). Being in the UK (240VAC), the in-built resistor is bigger than what Seeburg used (Ron once told me) but it still gives a good indication. Once the read out pulses are good, you can check the trip SCR and trip relay etc.

Norman.

[paullperth]

Hi Norman
I am going to build a test lamp tomorrow. I will report back when i’ve had a chance to run some tests. Difficult during the week with pesky work getting in the way

Paul

[paullperth]

Quick update: I built the test lamp this evening and ran a very quick test.

I get a flash on the neon via Write in pulse when I enter a selection. The neon flashes as the mechanism scans when connected to Read Out. Constant glow at the HV/+150v test point.

I’ll do the more detailed detent switch tests in a day or two.

[jukenorman]

On the face of it, that would point to a problem with the sense/trip circuit. Is the plug/socket from the tormat clean? You mentioned earlier that plugging/unplugging the tormat plug didn't initiate a trip - this isn't regarded as a reliable check but most times seems to work (in my experience). Have you checked the SCR? According to flippers.com, 2N5061 is a substitute.

Norman.

[paullperth]

Thanks Norman. I have some 2N5061s here on standby

I read somewhere that you can check the SCR by tickling the Gate with the positive end of a grounded 1.5v battery. It is probably just going to be easier to swap out the part. Annoyingly the SCR is the only significant part of the SCC not changed!!! I did test it with my Peak component tester (https://www.peakelec.co.uk/acatalog/dca75-dca-pro-semiconductor-analyser.html ) and it didn’t show any errors but I will change it and let you know how I get on.

Paul

[jukenorman]

Another thought, is there continuity down the sense wire ie tormat plug (point to case). It should be quite low, possibly less than 2 ohms, if I remember correctly. The SCR is really just a gated diode.

Norman.

[paullperth]

Quick trip to the workshop before work and it seems that I have continuity across the pin and shield of the RCA plug. Didn’t have time to do anything more but I will have to take a closer look tonight.

[paullperth]

Update: ok so I am now really confused. Apologies for my ignorance here but the cable to the RCA plug has three elements; a green “hot” core going to the centre pin plus a black wire and shielded braid connected to the outside of the plug. Why am I getting continuity across the black and green wires? Shouldn’t they be separate if black is ground and green is the write in pulse?

Again, sorry if I am missing something here but I am eager to learn.

[jukenorman]

The sense wire is just a wire loop through every tormat toroid so what you should be seeing is its resistance when you measure from shield to core of the RCA plug. I searched the forum and there is a post from Ron Rich saying that it should be around 2.5 ohms. So it depends what you mean by "continuity"? Theoretically it could be just slightly lower for a 100 selection tormat.

Norman.

[paullperth]

Sorry, I should have been clearer. When I use my multimeter on the “buzz” setting (to indicate when a connection between 2 points is being made), I get a beep when I put one probe onto the green wire and one on the black. It is making a connection across the wires. If I touch the centre pin with one probe and the outer rim with the other it also beeps. I thought the centre pin was the pulse signal and the outer ring the ground? Maybe I am just too fixated on thinking about traditional RCA plug wiring for audio.

In terms of resistance between the two, it is around 1.8ohms.