new to me 3700 attempting to bring it back to life

[jukenorman]

There's not a great deal in the power supplies which you can probably tell by looking at them! The diagram for the 554 is in the 3700 manual and I have posted the 561 below. The only difference between them is the method of DC rectification as far as I can tell. And from my cursory check, I can't see them being interchangeable because of that difference - it's maybe no surprise that the 561 pops the breaker! It would be quite easy to rewire the 561 to a 554, you could just leave the bridge rectifier in place and use half of it (ie two diodes).



Norman.

[sh0rtlife]

Aug 13, 2024 19:08:05 GMT jukenorman said:

There's not a great deal in the power supplies which you can probably tell by looking at them! The diagram for the 554 is in the 3700 manual and I have posted the 561 below. The only difference between them is the method of DC rectification as far as I can tell. And from my cursory check, I can't see them being interchangeable because of that difference - it's maybe no surprise that the 561 pops the breaker! It would be quite easy to rewire the 561 to a 554, you could just leave the bridge rectifier in place and use half of it (ie two diodes).

Norman.

thats actualy usefull

sorry i should have been a little more clear..there is a cap that connects the free play switch to the 12v breaker...from what i can see it has no name or designation..its a100uf 24v cap..the 561 causes it to explode

but...it doesnt look like it matches how the 561 i have is laid out..so..maybe the 561 i have has been re-wired weird
but the fact it has the voltages on it helps considerably

maybe this will help as well

so make note of the "thin" out of place looking pink wire pin#7...thats the 554 psu(this unit is dead dead..no power period)

the orange-ish #12 is the 561 psu far left on the top tied to a single transformer wire red/yellow , the red/yellow wire does NOT exist in the 554
the "brown" wire #7  runs the 4 rectifiers as noted

[sh0rtlife]

so if i understand
i need to move some things around
#7 gets chassis grounded
12 needs to be moved and just double diode
what do i do with the red/yellow striped transformer wire? as it looks like its a primary leg of that 50v coil

[sh0rtlife]

so i blew up and printed both psu wiring diagrams, then traced each pin in a different sharpie
#7 and #12 were the change
more importantly the red/yellow tracer transformer wire needed to be grounded to the casing

moved all the related wires to the same spots seen on the 554 then used 2 of the 561 diode's and bingo, it works..no faults with power...so MUCH thanks!!!!

of course it seems with these machines no win comes without a new problem....FFS

"new" 3700- "R" selection does nothing..probed it and i KNOW for fact its in the selection switch contacts..yay...thankfully ive got spares but they suck to work with
"old" 3700- i just finished pulling apart and doing some repairs, a few slides were shot..that aperantly slipped by me when i rebuilt the unit, as well as 2 old contacts had broke off so had to replace them as well.....so its fixed..right...NOPE
now the latch is chattering......it didnt do it before i rebuilt the selections..it didnt do it after the first rebuild..but now it does it for no good reason....
held down the relay for it and it locked, tryed some known bad selections and they worked..so now i need to figure out why the latch is chattering

[jukenorman]

Before you attempt to convert the 561 to a 554, you need to check the AC voltages at the secondary windings that are used for the DC. The voltage at these windings is not marked on the drawings and although the other transformer windings on both power supplies are identical, I have just checked and the transformers have different part numbers.

I have now just re-read your last post and discovered that I am too late with my warning! Just to double check that what you have done is OK, can you measure the DC voltage at the 554 and the also at the modified 561 to see whether they are the same. Measure at power supply plug pin 12 to ground.

Also, if you're now using the modified 561 and the DC voltage is too low (which I suspect it might be), then that is maybe causing other issues like your latch problem.  But we should still be able to modify the 561 to a 554 once you confirm the voltages.

Norman.

[sh0rtlife]

Aug 14, 2024 8:26:58 GMT jukenorman said:

Before you attempt to convert the 561 to a 554, you need to check the AC voltages at the secondary windings that are used for the DC. The voltage at these windings is not marked on the drawings and although the other transformer windings on both power supplies are identical, I have just checked and the transformers have different part numbers.

I have now just re-read your last post and discovered that I am too late with my warning! Just to double check that what you have done is OK, can you measure the DC voltage at the 554 and the also at the modified 561 to see whether they are the same. Measure at power supply plug pin 12 to ground.

Also, if you're now using the modified 561 and the DC voltage is too low (which I suspect it might be), then that is maybe causing other issues like your latch problem.  But we should still be able to modify the 561 to a 554 once you confirm the voltages.

Norman.

i will double check it, thanks for the warning...just to make sure there are not any "future" issues with it..i too made note of the part number change, my suspicion is that the red/yellow tracer wire is grounded out internaly on the 554 transformer and is an actual lead coming out of it on the 561..yeah its a guess but the fact that it works? as well as both scematics show things as the same save for it just encourages me that its probably the only change

the 561 is in the "new"  machine, i ran random letter/number cycles thru it every letter(except R as that selection is not making connection as it should) , allowed it to run both sets of "pre select" ...i have the  tone arm held up with a piece of fuel line so it never needs to touch a record(works great for testing) as well as the tone arm trip switch with a shim in front of it to fool the machine into thinking "end of record" which allows me to cycle the machine very quickly, ran about 50 selections thru it and it never skipped a beat

the latch issue is in the "old" machine with the old 554...i went thru its keyboard trying to solve the only A works, and..if i MANUALLY hold the RY1 relay down the latch doesnt chatter, all selections work..so im assuming its a ground fault  of some kind

at this point..provided the voltages in the 561 are the same or very close then i can see daylight at the end of the tunnel

"new" machine needs selection R adressed and a re-check of the 561
"old" machine has an unknown chattery latch but holding ry-1 down it doesnt chastter

i recalled an old post about a chattery latch, checked the timing board, so i swapped control boards, still chatters, swapped control board into the new machine, no chatter..so im 100% its in the selection keyboard assy somewhere, just not sure the how and why

really sorry about the extra confusion of working on 2 machines at the same time...but between your help, and having a second machine to swap and test with i feel like im making some pretty big steps forward in short order....selection R aside i have 1 completely functional problem free machine

[sh0rtlife]

sometimes all you can do is laugh

so i took out the selection assy a few days ago, spent the better part of a week( a few hours every morning and a lil in the evening) re-working and getting all the contacts in the a-v selections working..i had it COMPLETLY apart, replaced several slides that were cracked, replaced a few more of the pressed in contacts and ran my bench top powersuppy at 6v with a test light on every bloody connection till it was faultless, partialy re-assembled and re-checked it again, fully pressed the retainers back in place tested it again, installed it and had chatter that i dint have before

so i just pulled the whole thing back out again, bench tested it and..still good..WTF?!?!?!

connected it to the "new" machine and chatter away..ok proof its in the selections

so heres the thing 1-0 has never given me much issue but i did replace several broken contacts in it months ago when i did the a-v side but again its all worked since

so i start chasing wires..hmm so theres 2 ground lines 1 runs thru the a-v side the other runs thru the 1-0 side...well hell lets try something, i ran a jumper from the ground wire on 1 and the ground wire on 0..conveniently they both goto contact switches next to the latch 1 yellow 1 pink, jumped them and bingo no chatter

so somewhere in my fixing a-v, 1-0 descided to throw a fit and require work..but hey i know where the issue is right?!?!?!?

ima say it right now..the way the selection switches? contact slides? are made are ALWAYS going to be a sore spot on these rigs, age, bending, adjusting, heat, and perpetual flexing every time a selection is made..they WILL always be a high fail point weather or not they present right away is the thing

my brain is re-working the design when i cant sleep to replace it all with actual switches mounted off the backside of the slide assy so the rods hit a actual clicking switch..something of a perminant fix

just finished going thru 1-0 selections found 2 cracked slides..replaced them..everything checks out with the bench top supply and test light..so im stumped

any ideas?...im still pretty confident its in the selection keys im just not finding it
i need to verify but i think its chattering the ry1 relay as well

[jukenorman]

If you've been through the pushbutton switches themselves, what about the latch switches (Page 4B), are they OK? They can often be troublesome.

Norman.

[sh0rtlife]

Aug 14, 2024 19:26:50 GMT jukenorman said:

If you've been through the pushbutton switches themselves, what about the latch switches (Page 4B), are they OK? They can often be troublesome.

Norman.

funny that, ive had ZERO issues with either machines latch switches, mind you the "old" machine was "updated" and had that additional latch switch added(but the new machine was never updated), which was my freeplay issue, i left it with its over gap out of adjustment, ran a wire off each side down to the slug rejector plug, then wired the coin switch paddles together, having the free-play jumper in place, you drop a coin in, it trips the paddle and  trips the latch switch, and your ready to select..probably the most elegant way to bypass the BO/AC to play off a coin but not need the BO/AC..bonus..the latch isnt sitting there waiting for a selection

as of right now..with the "new" table in the "old" machine i have 1 100% working machine..no "known" faults...played a random selection on every number and letter and played without issue

the key select/latch chatter was another set of contacts that i didnt replace failing and another pair of sliders with hairline cracks in them(internal parts of the key selection)..im REALLY happy i bought that 3400 selction for parts..ive used about 75% of it at this point. i was going back and forth with the selector assy in both machines chasing the jitter just to make sure i had it solved

the "new" machine has the old table in it with the worn cam, so thats the next thing on my list....

playing with the selector assy i found out that the R selection is NOT the selector assy in the "new" machine...or atleast i dont think it is as i had the R not working on either selector even once i solved the jitter and have played R selections in the "old" rig.....so it may be table or wiring related

[sh0rtlife]

checked the voltages and while the #12 ends up .4v low it doesnt seem to have any ill effects and could just be the fact that its old the winding wires prior to the diodes are off by a over.1 so double that and you end up with .3-.4 ...thankfull all the voltages in the diagrams are mentioned..save for those 2 wires.........

wifes been running random selections thru the old machine and aside from complaining about volume its been faultless

so im going to shoot some pics of my remote valume control maybe one of you guys can help me wire it up..ive been thru the manual as well as the mini manuals and even the volume control install, but this one isnt the same...its "similar" but when it was installed on the "new" machine when i got it..it would turn the volume down "hum" but not up the volume, and the mute worked..so i know somethings not quite right

rebuilding the deck for my wife so havnt had much time to work on the new machine...still a head scratcher as to why R is out

was thinking about running a pair of wires off the tone arm end of record switch as a "reject record" switch in a remote top box for the rig, along with a credit switch, i figure the reject record would be good for a stuck skipping record, one that wont star or  any manner of defect as well as, well thats not the song i thought it was.....means my wife can "fix" the issue and make a note for me for later

[sh0rtlife]

ok so heres the "unknown" volume/mute control, like i said..i suspect it was wired wrong as it only partialy worked..also..the 3 screw hookup on the top..pretty sure thats a mic hookup but i cant find any info on that style..whats the pinout?

[sh0rtlife]

oh yeah, this is the kind of sillyness ive been dealing with on the selection keys

[batman]

Hi

i read through your post and have a question please. I have a Wurlitzer 1050 with a similar issue with the record take out arm not completely moving all the way down which just recently started. If I missed it I apologize but did you identify the chaise and or fix?

thanks

[sh0rtlife]

Sept 7, 2024 23:24:54 GMT batman said:

Hi

i read through your post and have a question please. I have a Wurlitzer 1050 with a similar issue with the record take out arm not completely moving all the way down which just recently started. If I missed it I apologize but did you identify the chaise and or fix?

thanks

so on mine its the transmission is worn, specificly the bearing on the cam bear has lost its balls and it just 2 shells rolling around, thus its got slop
if you look at the "big" gear in the trans there is a small cam gear and roller that runs in a groove

select a record, and when the arm stops moving hit the service switch, then look at the transmission, note the return spring for the takeout arm, it is connected to said cam and roller, use a small screwdriver and "lift" the cam roller and if the arm flops down and the bearing moves up, youve found your issue

i HAVE NOT solved it yet, as ive been far to busy, but ive ID'ed the issue..its a matter of pulling the transmission dissasembling it and seeing if i can find a suitable replacement