JBE series 3 restoration. Next on the list....

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Unic
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Re: JBE series 3 restoration. Next on the list....

Post by Unic » Thu Sep 27, 2018 1:40 pm

I think I have almost all the data to complete my diy control unit.
It's only lack the potentiometer values confirmation.

Thanks in advance for any help, here. :)

Ant
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Re: JBE series 3 restoration. Next on the list....

Post by Ant » Sat Sep 29, 2018 6:41 pm

I dont have it here at the moment to check, but i think thet were both 5k lin
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Unic
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Re: JBE series 3 restoration. Next on the list....

Post by Unic » Sun Sep 30, 2018 9:48 am

Thank you for this confirmation, Ant.

I already design a layout to receve this 18v voltage regulator with an extra 12v regulator aside to control the bistable relay that will handle the power button, the speed switches buttons and their respective leds.

I am waiting for the parts right now. When done I'll post the result here.

Regards.

Unic
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Re: JBE series 3 restoration. Next on the list....

Post by Unic » Mon Nov 12, 2018 7:49 am

Hi everyone,

The control unit for my JBE Series 3 is ready and it work fine.
The Technics SL-2000 schematics matches (posted the page above). So I confirmed that the pitch potentiometers are 5K lin and the ceramic capacitor is a 10pF.

At first , I had some speed issue (not stable) ; the problem was not in the control unit but in the motor circuit. I changed all the electrolytic capacitors in it. Don't forget the 1µF/50v blue tantalum capacitor, it is the responsible for this speed issue.

I recycled a computer PSU box for my control unit. The transformer is a 230v/12v/24v I had scavenged from a integrated amplifier, surely oversized for this use. The 18v regulator is a BC141 instead of the BFY51 (they are almost equivalent).

I "pimped" the control unit with a bistable relay (2 coils / 2 switches) to control de speed selection and an another relay for the motor the start/stop (1 coil / 2 switches), so I included a 12v regulator on my PCB layout. I also include a 12v stroboscopic lamp to control the speed.
20181031_142406_resize.jpg
20181109_225252_resize.jpg
20181109_225946_resize.jpg
As you can see, a found the JBE Series without feet and cover but with a Fidelity Research FR-64fx (great tonearm).
I quickly made some aluminium feet, with decoupling spikes. For now, they do the job.
The next step is the cover replacement.

Thanks for all the help I get from the topic. ;)

PS : Ant, I took the liberty to complete your schematic .
Image

Ant
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Re: JBE series 3 restoration. Next on the list....

Post by Ant » Tue Feb 11, 2020 1:05 pm

got the jbe back the other day, and immediately started fiddling.
nothing major, just fitting of the at150 cart and a change to the legs.

ImageJbe series 3 transfi legs mayware f4 at150sa by anthony cresswell, on Flickr

the legs are off the build i did for nigel, they were far to tall for the plinth i did for that one and were stuck to the original plinth with some sort of uber glue which was much tougher than expected. i had to bash them off the old plinth with a heavy rubber mallet............. :banghead:
spot on for the jbe though

ImageJbe series 3, mayware formula 4, audio technica at150sa on new legs by anthony cresswell, on Flickr

back into service spinning abit of steely dan, forgot how good it is
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Ant
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Re: JBE series 3 restoration. Next on the list....

Post by Ant » Thu Feb 13, 2020 1:43 pm

did some more to it.

i noticed something was going 'off' with it, and after much headscratching found that the azimuth was off. turns out that the rubber section of the mayware counterweight wasn't gripping so the weight had slowly slipped downward overnight and cocked up the azimuth.
it wants replacing really, its a little perished so ill have to find something as a replacement to do the job.
so i took the mayware off for now and put the audiomods that was on pauls 301 on it.

ImageJbe series 3 audiomods classic 2 audio technica at150sa by anthony cresswell, on Flickr

while i was at it i stripped it down and resanded and polished the plinth with teak oil, redrilled the arm board to take the audiomods mounting collar, and replaced the pads on the platter with new silicone ones. these are simply adhesive discs, and these were meant to be pump seals. but are the same size and thickness as the original blown sorbothane pads.

ImageJbe platter pod inserts by anthony cresswell, on Flickr

the left hand one is the original which is completely perished on the top. the top middle one is what the underside looks like, not perished but getting the remains of the adhesive off was not possible. couldnt just turn them over unfortunately, and the right hand one is a new silicone rubber one.
much better. the new ones actually grip the record. and look better. and it sounds better too.

ImageJbe series 3 audiomods classic 2 audio technica at150sa by anthony cresswell, on Flickr

now the audiomods arm is on it its blummuin lovely :mrgreen: got keith jarrett on now doing his usual weebing and deebing, ohing ahhing and all the other noises he seems to make while playing. can hear them clear as day and its giving me a smile. highlights how bloody good ecm pressings are too.
Hey, wait, I got a new complaint
Forever in debt to your priceless advice

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