KD200 oddities

[phillg]

I'm travelling pretty soon and the guy I'm going to see has a beautifully restored KD200 (well, it was restored some 25 years ago but is still in great condition). However, time has taken it's toll and it has a few issues. I'm restoring my Wurl but I know nothing about Seeburgs and I know they're entirely different.

These are the issues I'm aware of:

• One letter selection plays every number of that selection. I can't remember the letter, but let's say if I select "A4" it will play every "A" instead of just A4
• One selection plays every song on the entire machine (again, can't remember but let's say it's Q5)
• There's a loud popping sound as the machine scans. I'm guessing this is a mute problem but wanted to check there's no other likely culprits before I start looking

As I said, totally new to Seeburgs (so assume I don't know 'tricks', etc.) but promised I'd take a look for him.

Thanks!

[Ron Rich]

Phil,
Judging from what you have written--
All sounds related to me-- All sounds like a "dirty TES". I would advise you to remove the TES from the phono, remove the latch bar solenoid, and meter(s) from the TES, then wash it in hot dishwasher, soapy water. rinse, then re-wash it out side, (stay up-wind !!) with (sudsy, if you can find it) ammonia--rinse totally, --dry totally re-install parts removed, lubricate it and try it. Ron Rich

[phillg]

Thanks Ron, I'm there for 10 days or so, that should give me time to do this then troubleshoot when it doesn't work after I put it back together again!

[Ron Rich]

OK-- take a 12AX7 and a 2050 with you--probably won't needem--also take a 1n4004 or better--change that diode ! Stay away--at least 10 feet away, from the stepper on that thing !! Ron Rich

[phillg]

Thanks guys.

I'm now here with the phono and I can see what's going on. I've installed a new freeplay unit so it's up and working again (the credit unit caught fire a few months ago)

It's been out of action for 6 months or so and has picked up these two habits in that time

• It won't play Qs... Q1, Q2, Q3, etc - pretty much any of them although most of the other selections seem to work (got to go through and try them all)
• It's playing 'random' other selections - as the mech scans, it will generally play a random selection of 1-3 songs between A1 and C3 (only on the return scan, left to right)

Then there's the persistent problem with N5... it just plays randomly (has been doing this for some years, I gather). My guess here is the TES as Ron said, but before I take the machine apart does that sound likely?

As for the popping, I guess you're talking about the diodes in the mute circuit? Since they're old, I guess they can have had 'it' and replacing them would likely fix the sound during scanning.

Thanks

[Ron Rich]

Phill,
Do you have the K/L service manual there ?
Ron

[robnyc]

Jul 18, 2018 18:29:37 GMT phillg said:

These are the issues I'm aware of:

• One letter selection plays every number of that selection. I can't remember the letter, but let's say if I select "A4" it will play every "A" instead of just A4
• One selection plays every song on the entire machine (again, can't remember but let's say it's Q5)
• There's a loud popping sound as the machine scans. I'm guessing this is a mute problem but wanted to check there's no other likely culprits before I start looking

Since I've dealt with these problems in my location machines, I'll suggest the following:

Random tripping: As the mech scans check for sparking at the contact block under the Tormat. pay particular attention to the center contacts. If the center contacts are sparking at all it causes electrical noise that can overcome the filtering in the pulse amp and lead to tripping at random. This can be caused by rust on the center grounding plate -or simple wearing away of the plungers. the simplest solution is to loosen the adjustment screws that hold the block and raise it slightly and re-tighten the screws.  Check also for broken wires that connect the plungers. The original tiny wires are a bit too delicate (IMO) so I replace them with braided wire of the type used to connect speaker voice coils to the terminals. I've never had repeat breakage using those.

I eliminate the center plungers from the circuit and run a wire from the grounding plate to the selection receiver chassis through a 1 amp fuse. --Be sure to eliminate the grounding fuse in the mech if you do this modification.--

Popping noises can be caused by the above as well. There are also two sets of mute contacts on the mechanism. One on the vertical stack and another on the horizontal set called the "clutch switches".

Playing every selection error: This can be misinterpreted and not really be "every" selection butinstead a bunch of added selections caused by the contact block failure as above.  However, if one of the 0A2 tubes fails (it will be dark) the write-in current becomes excessive and all of a letter and all of a number will be 'selected".

Poor contact on the connectors for the tormat and keyboard can sometimes cause a lot of extra selections. Clean and slightly tighten the contact fingers at the edge connectors at the stepper box (upper left).

Make sure to bring a known good 12AX7 for the pulse amp. As these tubes age they sometimes develop hot spots on the cathode that makes them hyper-sensitive and have poor control of conduction. In these application that means error tripping.

Ron will probably have a few more ideas.

RobNYC

[phillg]

Aug 2, 2018 2:52:47 GMT Ron Rich said:

Phill,
Do you have the K/L service manual there ?
Ron

Just asked. I was expecting the answer to be no, but the owner actually has the service manual! He's digging it or for me now.

robnyc, thanks for the ideas - will take a look at the Tormat for sparking first

[Ron Rich]

Hi Phill,
I agree with all of Rob's suggestions except the addition of heavier wire on the contact block, and the elimination of the grounding pins. I do usually replace the wires on the pins, with 30 gauge tone-arm wire. I do NOT "add pressure" to the pins--these must IMHO, be set as lightly as possible. The tops of the pins MUST still be silver, and they should be flat, to slightly domed, with a burnishing tool. The silver grounding bar must still be silver plated. If bad, it can be turned over ( new mounting holes may need to be drilled), and re-installed. The
TMU contact rivets must be clean (use NO abrasives) and the area between each rivet must also be clean. A VERY light coat of 20 wt. oil may be used on both the rivets, and the grounding bar. The Detent switch, MUST, be free of pits, have silver left on the contacts, and be carefully adjusted (air gap too !) as per the manual !!
In the service manual--
Page 1287--Top AVC section
Check R-186 should be a 1 meg, check C-121 should be a 22 uf
At this point, also look at the mechanism. There must be a 2.2k -1 w resistor added to the switches. This was added to TB 655 between terminals 2 and 6 see page 2424
Power amp section--
Find pin 7 of xv253 (12AX7). Cut trace between pin 7 and junction of R-263--Bridge that cut with a 10k -1/2 watt resistor.
Page 16024-- TEU-1, change that "flower-power " (germanium) diode !! (CR-551).

Look at the 25PCU-1-- Look at pin 1 of the 11 prong plug and pin 6, of the 6 prong plug sockets. There must be a .02 / 600 cap connected there.
Also in the 25 PCU--- check the scan control assembly. It MUST have a .01/1400 cap soldered directly soldered across the motor run contacts9 which also should be free of pitting, and close very tightly. There also should be a three position terminal strip very near that assembly, which has two .01/50 v caps mounted to it. If NOT there, it must be added--these caps are wired in parallel to the add/sub coils (one cap per coil).
-
If all of the above is OK, and the TES has been washed as stated above,--your model K should run perfectly,--forever !
Enjoy your "Holiday" !! Ron Rich

[robnyc]

To be clear, I am -not- suggesting just increasing the plunger pressure if adequate overtravel already exists. However, this is one of the only areas in these mechs where routine wear will eventually necessitate moving the block up slightly to restore proper contact. The only other item that requires eventual adjustment is the detent switch.

IMO, there is no valid electronic reason not to eliminate the center ground contacts -als long as they are actually disconnected and a fuse is placed in the direct connection to the chassis. I've done this for 29 years on all my old retro machines on location. The later tormat machines eliminated those contacts for direct connection as-built.

The speaker "spider wire" is every bit as flexible as the #30 and does not fail in heavy use.

You and I have both seen machines where some Gepetto used 18ga zip wire and thus had to shove the block all the way up to maintain contact. My old friend Bill used to roar that "whoever did this should have his hands cut off...". He took this stuff too seriously.

Rob

[Ron Rich]

Hi Rob,

I spoke with Seeburg Engineering about the ground elimination, whom ever I was speaking to gave me what I thought was ( at that time) a very valid reason NOT to do that I have racked my brain for years over this--just can not recall what it was ? 

As for the way the production dept set the pressure, I watched them do this--stop the mech in the center of the TMU, dead center between rivets. Adjust the contact block for a minimum clearance between the horizontal (black) pin pushed through the plunger and the top bearing plate. ANY more pressure then necessary here, prematurely wears off the silver on the plunger pin !  I agree--twisted brade probably would work well here--I too have seen the 16 gauge wire, slobered, to those pins ! Also have seen many pins with no silver left on them --also have seen the fuse on the mech, and on the later "frog/flip type" read out contacts jumped out ??   Ron Rich

[phillg]

Thanks both.

I took a look at the tormat and it's not only correctly adjusted, but it's immaculately clean - it looks brand new. No sparking, runs smoothly.

I've narrowed down the behavior while investigating. One day it wouldn't play any Q's, the next day it would. Some times L7 will play, sometimes it doesn't (this happens to a variety of selections). My suspicion here is a faulty valve in the TSU - either the 2050 or the 12ax7.

The final fault could be related. The machine picks up false-positive selections. These are always 1, 2 or 3 (A1, C2, C3, etc) and sometimes 4 but can be any letter. The other numbers do not trip falsely like this.

Any thoughts? Never worked on a tormat system before, as you know, and trying to get my head around the workings.

[Ron Rich]

Phill,
I doubt either the 2050, or 12AX-7 is at fault--neither of these "know" which selection number has been "picked" ! Have you looked at the Detent switch ? Is it set as per the service manual--and clean--no pits/burrs ? Have you divided the read-out and Wright-in systems using a D cell ?
Ron Rich

[phillg]

You were absolutely right, of course.

I had to leave without getting a chance to check the detent switch or try out the battery trick. I'll be back in December, so I'll take a better look then.

Thanks for all the help, much appreciated.