Scanning problem on Seeburg 100b

It finds the pin going in the wrong direction. For example, when the the mechanism is at far left and a B side selection is made, the mechanism moves right and as it passes the selected pin it clicks. May pause for a second. Occasionally it will stop but not load a record. Most of the time it just clicks and moves on. Seems to cause a problem with pin reset too. I thought it would be in the reverse switch and I checked that. Seems correct per manual. Any suggestions as to what to look at?

Hi Eddie,
Well, iffin you had a copy of my "Seeburg Mechanism Guide--AND--read it , you would understand the process that the scan control uses --It does not-- go thru the "Reversing Switch", on any model, except the LPC, and APFEA-1 models, where the scan control subtract function, does. .
Your problem can be caused by any one, or more of the following: Miss-alignment of the segments in the SAU, pins installed backwards in the SAU. A badly worn contact block (frog). A broken/bent/miss-aligned frog holder.
Ron Rich

I have a copy. Must have overlooked that paragraph. But if it doesn't go thru the reversing switch how does it goes past a pin first time?

Hi Eddie,
You are confusing the TWO functions of the SA Unit--read page 10 of the Mech Guide--
Ron Rich

Eddie, it sounds to me as though the contact plungers and/or the finger blades that press against them are no making good connection.

Take a look at the plunger block in this E-bay auction:
http://www.ebay.com/itm/Seeburg-Model-B ... 5674b82da4
On the second pic you can clearly see the two sets of contacts that press the plungers into contact with the pins.
There are also contacts in the two stack of blades on the front of the mech that directly affect both trip and pin cancel function.
On those old machines the contacts there directly complete the ground circuit to power the trip coil and another set actuate the coils that cancel pins and punch the popularity meter.

If the machine is dirty it is almost certain that poor connections are to blame.

Read Ron's post above on cleaning contacts. that should be helpful here.

BTW: Has the amp been rebuilt?

Rob/NYC

Rob,Eddie,
If the mech motor "stalls" when the frog passes the non-selected side of a record, it can only be one thing--the grounding washer is loosing contact with the grounding bar. There are several things that can cause this, as I stated above. This can also happen on the selected side--in this case, the motor will stop at the detent point, prior to lifting the record. If the washer re-contacts the bar, the motor will re-start, and the phono will play the selection, or, making another selection will cause the motor to re-start, as another grounding washer is now touching the grounding bar, energizing the play control relay. Ron Rich

Ron.. On page 10, under Electrical Sequence of Operation... paragraph 2, last line. "The reversing switch also determines which of the two sensors and 'pin cancel coils' on the frog are in the circuit". This is why I mentioned the reversing switch in my original post. Apparently I am misinterpreting something. The pin bank has been disassembled and cleaned. As has everything mechanical on this machine. By me.

hi Eddie,
Yea--somehow you are not seeing that there are ---TWO---- separate circuits here---
1. The "washers" on the pins when the pin is in the selected state, make contact with the grounding bar, which energizes the "Plau (scan) control relay, which powers the motor--
2. The reversing switch determines which one of the 2 "sensors" on the contact block, are connected to the detent coil (also, the motor direction).
Hope that clears that up---
Ron Rich

Thinking out loud here. Yes I understand. But to my thinking, the reverse switch disables one of the sensors as the mechanism moves in the wrong direction. If something didn't disable the sensor it would ground every time as it went across. It's not a "dirty" washer or bad connection in the pin bank. A dirty or bad connection would remove the ground, not make it happen when it's not supposed to.

Ok, I hadn't had a chance to look at this page again till now.

Eddie, Ron is correct in that the click you hear is the play control relay inside the stepper box. The clue here (which i overlooked) is that sometimes the mech stops. That click is the play control relay falling out due to high resistance connection to the ground bus in the memory unit.

The reversing switch on the front of the mech does determine whether the A or B plunger is live.

Essentially, you have the unenviable task of taking apart and cleaning-polishing the grounding bus inside of the memory bank along with all the washers. Its likely there are also some individual coils in there with shorted turn and which draw too much current. Look for any obviously blackened one and measure --all-- of them with ohmmeter. I don't recall the impedance, but you can deduce it by measuring several and finding the range.I believe Vern Tisdale still sells those or, you can just rewind them yourself -this is what I had to do in the 80s.

Rob

Gents,
IMHO, "Shorted coils" in a SAU is something that there is NO excuse for !! Early WSR-5's called for a 2 amp SB fuse to protect the coils, later WSR's called for a 1 amp SB--IMHO, a 1.6A. SB, is the MAXIMUM size fuse to be used there. Use of this size fuse will prevent overheating coils--a "nasty job" to change !! Ron Rich

Like I said before...the pin bank was totally disassembled and cleaned by me. If it is losing ground why does it only do it as the mechanism passes the selected pin? Why would it be doing it anyway? The opposite side is supposed to be active when the mechanism is moving in the wrong direction.

Eddie,
Last try---
You are still confusing the functions of the SAU, and reversing switch--
The rev switch has four segments, on that model. The functions of it are shown in the service manual.
The SAU has two "functions". 1. To "pull a pin". 2. To connect the washer under the pin to the grounding bar, which, in turn pulls the Play control relay, which in turn, powers the motor.
"Pulling a pin" will (hopefully) connect the washer to the grounding bar, in exactly the same fashion as holding the spring loaded switch in the "on" position--motor will run --but if no pins are pulled (well, the spring loaded switch when held, also shuts off the 24 vac to the sensors, so it can not detent when switch is held), phono will not detent !
What is happening on your phono, is the "dresser" on the block is hitting the "pulled pin"--see what I wrote, above, for what could be the cause of this-- Ron Rich

well I am a little dense, you have to break it down. I see what you are saying and it makes sense now. At least I guess I do. The dresser is removing ground momentarly as the mech passes..

Yep--ain't that whut I writ a couple of daze ago??---
Ron Rich