Seeburg 100r Recap question/s

Hello All,

I've just started the process of recapping my Seeburg 100r's Amp and receiver using the kits from Jukebox Friday Night. Today I nearly finished the WSR7 receiver except I have a question regarding the wiring of the the 330uf run motor capacitor. Does polarity not matter for this cap? Neither the original metal housing nor the new Dayton brand cap have any polarity markings. The original has one terminal connected to a red wire and a black wire while the other terminal has a single white wire. I'm sure I will have more questions when I get to the amp section, so any help is much appreciated!

Or does the polarity not matter because this is an AC cap?

catboxer wrote:Or does the polarity not matter because this is an AC cap?

Motor run caps are non-polarized. The only concern regarding connections is when there are multiple sections with a common low side such as on the mechanism.

Rob/NYC

I just started re-capping my hf100r WSR7-L6 receiver and MRA5-L6 amp as well last night, I just have the last 2 caps C1 & C6 to finish.

I have found YouTube videos of someone doing the amp MRA5, he has a whole series of videos for each cap on the amp.
Example this one is for C12, C13 & C14 for the amp:
https://www.youtube.com/watch?v=8vEDkf5eekQ

That's awesome, thank you. At first I couldn't locate the remaining 5 caps on the receiver, but they were under that protective metal shroud.

Ron,
I would NOT re-cap as this gent does--I don't like a "straight wire connection"--
As for the oil filled AC cap in the WSR, Rob is correct. At one time in the past, this type cap was usually marked with a "red dot", to indicate the "positive side"--but in reality, as I understand it, there is no such thing in a bi-polar cap. BTW, you only need change it, if you are using the stepper ! It is NOT used as a "Motor run, or, start cap", here.

I don't like how the guy did the caps either, more of another reference as to where the specific caps are.

Sometime in the 80s this 100R was converted, or hacked, into running a solid state amp. Is it possible to get an original connector for this hacked together RCA plug? Or was it always a mono RCA? If so I can just install a newer cleaner male plug. This is coming from the selector unit and was plugged into the SS amp.

The 2 prong speaker output jack plug was also cut off, however that was kept inside the cabinet.

The "R" was mono, while it could be converted to stereo as I did with one,Tthat has not been done with yours.

I see the original tonearm assembly hosting a retrofit stereo cartridge. That -can- be good but there are a few caveats. Most of the adapters I've seen wired the two channels together in parallel. That is best for reducing distortion. A few wired only one channel, or worse, wired the two in-series in order to get more output. This emphasizes distortion from stylus and record wear. That cart appears to be the later types used from 1966-on. It has around 460 per channel of DC resistance on a meter, If properly wired parallel you will see half that on a meter.

Another problem is balance. The original mono cart is appreciably heavier than that later stereo one. If the adapter doesn't add enough weight, or the counterweights have not been ground down the arm will bias toward the approximate center point of a record and cause distortion and wear at the beginning and end of a record. Select a slot with no record and let the arm settle. Does it bias toward the middle? Turn off power and move the arm towards the turntable as far as it will go, release it and see if it swings back to that center point. The arm should be free to follow the record and not biased in any direction.

The tonearm plug was originally an RCA.

I suggest removing the silver capacitor that is across two motor connections at the right of your pic. these have been known to "pop" -sometimes violently.

Rob/NYC

What would you replace the .1 mfd 600v cap with? And where do you order one from?

Just cut it out. It was originally there to reduce noise when the mech reverses. Seeburg eliminated them sometime in the early 1960s.

Rob

Thanks Rob, incredibly informative. I finished up the receiver yesterday and was hooking it back up to the Solidstate amp just to make sure everything is still working before I tackle the amp. I'll take a look at the balance of the arm.

A quick Google search didn't turn up any guides on converting the amp to stereo, do you have any resources on the process? If the balance or output wiring is off, what are the recommended cartridge options available today for either mono or stereo operation?

Thanks so much!

Guy's
Seeburg eliminated that .01 cap in the mid 50's--and suggested that it be removed from all older models, at the same time.
HOWEVER---they also cautioned that it was imperative, that when eliminating it, the reversing switch MUST be adjusted exactly to specs. ( I have see the "explosive results" of two of these caps blowing a hole right thru the plastic mech covers-- Both were the "John E Fast" brand,brown caps) Ron Rich

catboxer wrote:Thanks Rob, incredibly informative. I finished up the receiver yesterday and was hooking it back up to the Solidstate amp just to make sure everything is still working before I tackle the amp. I'll take a look at the balance of the arm.

A quick Google search didn't turn up any guides on converting the amp to stereo, do you have any resources on the process? If the balance or output wiring is off, what are the recommended cartridge options available today for either mono or stereo operation?

Thanks so much!

OK, I modded two machines from that era for stereo; and R and JL. The R was seemingly a natural due to it's four speakers. that machine had already been retrofitted with a T stylus arm assembly and cart, but was wired mono. I used a pink TSA-4 from a PFEA1U(?). This allowed me to repurpose the original mute mech cable for the pickup since the squelch wire could now be used to activate the mute/squelch relay in the amp. I just drilled two steel stock rails to mount the amp on the rear door and placed a plate with DPDT switch for the motorized volume control in position to line up with the original volume hole. It sounded "OK" given the limitations of the original cart. The main reason for all this was to replace the original amp which had a bad output tran, and use an amp I was not going to ever use elswhere.

On the JL I simply mounted a later arm-cart (ground weights to balance) and left it mono. The only mods there were a real tweeter and 12AX7 preamp built in-place of the 5879 pre. this was done to get added gain so that the lower output "new" cart would properly saturate the AGC. Probably no surprise that machine sounded better than the R.

I do suggest that you be careful in adapting any later amp -whether juke or consumer type. The juke amps had a lot of tone shaping that appears to give large bass boost, but rolls-off as volume is increased. This concept should be kept as the speakers are not really capable of dealing with deep bass.

What SS amp is in there now? A pic would be interesting.

Rob

Thanks for the information about the capacitor on the mech.

I will be taking mine off now, I have already adjusted the reverse switch contacts based upon the manual, so I should be good.