The first thing Steve always told me : Check your supply voltages !!!

These old PSU need attention
The main problem on my machine, finally seems to be a broken Transport PSU ..


Send me a PM , if you are interested in JH 100 schematics etc.

Thanks for the reply!

All voltages are good...also checked MDA.

It seems that it’s the tach voltage getting from the take up side into supply side.

If I unplug reel motors and check the dc offset I can adjust at tp1 and tp2 for close to zero volts on each.
If I leave my volt meter on tp1 and spin the supply reel by hand the volts do not change (volts stay close to zero)...if I keep my volt meter on tp1 and spin the take up reel by hand I see tach voltages rise on tp1.
If I do the same test at tp2 the tach volts rise when I spin the take up reel by hand but not when I spin the supply reel.

Thanks

Is there anybody with a JH100
that has 8 Power Transistors on the Transport PSU ( MDB Heatsinks ) instead of 4 ??

There is a Mod ( Pic 3 ) , but my machine has BUY69B with 0.27 Ohm on the Heatsinks, not the DTS-423 with 0.39 Ohm

A orig. MCI scan of the Transport PSU would be much appreciated !!!

THANKS !

Hello team,

I know it's been a while since I have chipped in, but I would like to give everyone and update and some hope.

The passing of Steve Sadler has been a big shock and there is not a single week, I don't think about him, his advice, his attitude to problems in general, his untiring commitment to be self-sufficient, kind, somewhat patient with idiots, but never not calm in the face of MCI meyham.

I miss him and am utterly grateful, that I had the chance to learn everything I know about fixing my machine from him.
It's hard to imagine, what Randy must have been through in the weeks after Steve's passed away, but I wish him all the best. He's one of the last MCI sensais, so we should support him and make sure he can be there for us who are keeping these machines going.

Onto my first point.

For everyone who went through the mammoth task of restoring their MCI only to find "the machine is sounding too boring" there is two possible reasons, why that could be the case:
1.Your engineering/taste is hella boring and/or 2. you don't know about the MOJO cheat code...

If you guys check the photo I have attached, check the top left quadrant and notice the two brass jumpers... THESE ARE THE KEY TO A WORLD OF SOUND.

They pull out and if you plug them into the only other position they can go in (just realised the jumper on the right has three positions, but you can go with the 9o'clock position ). your 15ips/30ips speeds on your main switch are now 7.5ips/15ips...

Take a deep breath.

YES. You now have an absolute tone machine on your hands. You bias needs some re aligning so you can get the most out of your 7.5ips setting, BUT it doesn't stop there.

If you use your VARI SPEED on your 7.5ips setting you can go down even more and thats where you enter The Funk.

=========================================

Now onto another issue, that has been bugging me and my JH16 since day one, couldn't be solved with multiple session with Steve, but got finally solved by yours truly.

Some of you might have had that same problem and found this threat on the interweb:
https://groupdiy.com/index.php?topic=53146.0

I'll put it bluntly - YOU NEED TO GET GROUNDED MAAAAAAAAAN.

Basically - if you connect the ground of anything ground on motherboard/torque board or in my case the main heatsink frame on which the motherboard sits directly to the ground pin of your IEC cable (there is probably a slicker solution) - THIS ISSUE WILL DISAPPEAR INTO THIN AIR.

The night I found this - it blew me away and this machine has been A TOTAL CHAMPION since.

=========================================

Onto music... because we can talk about Molexes, ICs, solder joints, tape creep and autolocators until the cows come home, but these things really excel in the field of music:

This album was entirely tracked on the JH16, with only a handful of overdubs done on tools. Everything was like a session in 1976 with multiple reels and everything stayed on the reels and stuff got bounce down to tracks... glorious and not a single issue with the machine.

https://www.nme.com/news/music/willi...-heavy-2641959

This was an EP, that started with a Soviet-era Lithuania sonic brief and the machine and a WEM copy cat did all of the lifting on it.

https://www.youtube.com/watch?v=qrN4BYpElpI

THIS ENTIRE ALBUM went through the machine when it got mixed, so that's a great example of how FRESH the machine can sound and how 808s are NOT an issue - mind you - when lining it up, my lowend starts to drop off at 26hz and thats a db down from where 27hz is...

https://www.youtube.com/watch?v=bjGlrRxoclw

Here is another great example of a shroom infused session bearing some classic tones via the JH16:

https://www.youtube.com/watch?v=mRcAwUbVQFM

And this whole record was also tracked via the MCI:

https://www.youtube.com/watch?v=0VJHESil60g

=========================================

My method when tracking with the MCI is the following.

I have 24 groups on the desk.
1-16 go to the MCI and the output into Tools
17-24 go straight into Tools.

I send everything, that I'm tracking to my MCI channels and a reduced version of the basics straight to tools.

Now I keep the machine in repro and send my headphones of the 17-24 straight to digi channels, BUT I monitor only the repro and I can exactly dial in how much I wanna push tape as the takes are going down.
So its essentially a real time dump and when you send a click track to channel 16 at the same time you'll see there is next to no drift.
Come overdub time - I send my new MCI repro channels out of PT 1-2 and what the backing track/already recorded material out of PT3-4 BUT I insert a time adjuster plug on the master channel of PT3-4 and delay that by 16694 samples (when working at 96kHz) and now my prerecorded music that everyone plays along to (with headphone sends prefader on each channel) AND my new MCI repro real-time dump are perfectly in time for monitoring the two.
Once the take is done I select my MCI channel, knock them back by 16694 samples and send them out of PT3-4, ready for another overdub.
That obviously means I record two tracks per sound, but we all know its not 2002 anymore, so hard drives ARE MASSIVE and if you keep good session hygiene, then the audio file folder sizes won't outgrow all the digital audio, that has ever been recorded, by the time you're ready to prep.

=========================================

Good luck!


RIP. Steve Sadler - you're being missed <3

Fresh cabeling , 4 x 2 new DTS-423 per board ... problem solved !

I found a 60 page PDF manual for the JH-100 Transport !!!!

Send me a PM , if you are interested ...

New Reel Motor Bearings

Good evening

After a lot of "trial and error"
I´ve got a working transport on my JH 100 !
Rebuilt PSU, "Massive Molexia" , dead transport switches, new motor bearings, black + red sockets etc. .. you name it

Is there any available drop in replacement for the old ELEC-TROL reed relays ? ( Pic 1 )

I know MCI developed a FET upgrade, i´ve got them on 6 Control Boards ( Pic 2 )
but they are hard to find ..

Thanks !

Well done there. I doubt you will find those relays. Maybe copy the artwork from one of the fet boards you have, and make more fet boards. Transfer the trannys and hardware to the new boards. Or make a little board containing a new style relay that can drop in.

Thanks Radardoug !

A little board for a new style relay , okay
but what is a functional replacement for the yellow ELEC-TROL reed relays ?
I can´t find any information in the manual ...

from " Analogrules.com "
Electrol - RA30321911-02 : No Direct Replacment Available


The old control cards have this combination installed ( pic1 )

and there is a yellow relay on each channel board in the drawers , also RA30321911-02 ( pic 2 + 3 )

i found a mod on one of the newer cards , without any relay part number ( pic 4 )

I'm not sure if that reed relay is a changeover contact or just a normally open one. Most reeds are just two contacts. So any single pole relay will work.
You need to use one with telecoms type contacts designed for low voltage low power or audio.
The table at Analog Rules tells you what you can use, or copy yhe fet switch board.

I bought some spare Control Boards, so the problem is solved to begin with

But there is one last thing :

The OFFSET NULL drifts over time

I did all the stuff recommended on AnalogRules.com
http://www.analogrules.com/MCIxport001.html

Incl. new VRegs in the PSU, new 741 ICs, again a massive cleaning / resoldering the Molex connections,
Ground Mod, Feed-Thru jumper on the boards, new IC sockets etc.

Adjusting the OFFSET NULL works great, but 15 min. later the values have changed
i readjusted the OFFSET NULL , but after a while the values are wrong again .. ( lower than before )

Any ideas ? Thanks !!!

Offset Null Solution :

I´ve tried different LM741CN
in the " Steering " ( IC1 + IC3 Analog Torque Board )
and found a combination of chips that works great to get the Offset Null down to 0,00x DC
without drift over time !


Update: Cheered to soon ...
The Offset still drifts to around -0,3 - 0,4 VDC over time on both test points

Hi Guys,

So glad I found this thread. Bunch of incredibly knowledgeable people on here!! I’ve heard the incredible ply kind memories of Steve Sadler and I’m sorry for anyone that knew him here. Sounds like a great guy.

On to my MCI journey…

I have a JH24, which when I set up did not work. After some research I recapped and cleaned both power supplies and success!! It worked, or so I thought….

The tape speed was not constant. When hitting TVI on the autolocater, I could see (at 15ips) the speed varying from 14.93 to 15.05 roughly. I tried unplugging the remote, but ‘heard’ the same result with out it. This was in fixed mode obviously.

I was having some lesson with Chris Mara at the time, and we pushed through so I could get my head around a few more basics, but then….(dramatic music)…..the machine stopped altogether. Specifically the ‘play’ function. It rewinds and fast forwards fine, but won’t play. The capstan isn’t spinning, but pinch roller engages against the capstan when play is hit. Tape tension seems fine both sides.
I recapped the PLL board and changed ICs, and cleaned everything I could see/reseated and wiggled and connectors. I haven’t attacked the analogue torque board yet, but I’ve read that if that was the problem the roller would engage against the capstan (maybe incorrect info?).


Any ideas etc very welcome, as I wait for some ICs to come for the analogue torque board.

Best!

Chris

Up and running !

MCI JH-100 from 1975

In tribute to Steve Sadler

Email me a good quality image of this. We've broke ground on the new studio and I'd like a copy of this to put on the wall in the foyer. My gear will be coming out of storage soon and I'll be back at it to get the JH16 and JH110 up and recording.

Brian

Okay, the machine still needs some more fine tuning on the outputs .. channel 3 has a hotter output

But why is the original track ( first track, imported from CD )
less dynamic than the same track recorded to Tape and back to Pro Tools ???

Use a modern low offset opamp. OP177 is good.

Is this a drop in replacement ?

Your original track is severely limited or, maybe even clipped. The wonders of tape inconsistency maybe have given it some variation.

Thanks !
i thought the " wonders of tape inconsistency " have minor effects

Depends how well your machine is aligned. Looking at that, I would say not well. But its hard to judge just from the waveform picture.