AMPEX gurus out there? MM-1100 trouble...Bo??? (update#1)

[sverige_cruz]

Hello everyone,

My friend and I are having a bit of trouble (i.e. Pain in the arse) setting up his AMPEX MM1100 8-track. I will begin with a history of its problems, and perhaps some/few/one of you can help us out, please?

* got the machine from seller - played a test tape (tones) but would gradually slow down

* started to blow the fuse for the 27V power supply - no power to reels or transport control box

* checked transistors in 15/27V power supply - replaced 2 (2N4348)

* turned on machine - stayed on - in play mode (tape or no tape) take up reel spins - capstan does not spin - pinch roller does not engage - transport control box lights went out - VU meters sitll on - could not stop take up reel - shut down machine

* cursed the guy who sold the machine

* replaced the opto-isolators in the MDA - replaced 6 faulty transistors in the MDA - replaced fuses

* turned machine on - checked voltages 15/27/39 all OK - attempted to normalize reel servos & make tension adjustments

* in play mode take up reel spins (with tape on, it becomes very tight) - lights on transport control box out - capstan does not spin - capstan pinch roller does not engage -*BUT* the fuses are still intact - after waiting about 1 minute, flipping the power switch turns on the machine - rewind/ff/stop work - play doesn't engage capstan/roller, but engages takeup reel

so...this is where we're at now... stuck with protools till we fix this thing. Any & all help is GREATLY appreciated!

Best Regards,
Jesus Cruz

 

[soundguy]

post this on the ampex mailing list, there are very helpful folks there that know those machines inside and out.

http://recordist.com/ampex/apxlist.html

dave

 

[sverige_cruz]

Thanks, Dave -

I'm currently on that list, and been searching the archives...but it's way slow (not to mention there are millions of posts and no way to search all of them...) I've just recently posted there too. My friend has tried talking to a guy at BASE (http://www.analogrules.com/index.html), but he said they're pretty busy to be answering questions via email/phone. We did manage to get a "how to jumper the dummy plug" for the capstan speed reference, though. This thing has been a beast...but we're dying to hear it. Thanks, again!

--Jesus

 

[soundguy]

do you know anyone with a spare transport control card? I used to run mine with a 1200 transport card and it still was a bear to deal with. The transport control is especially frightful on that machine and I could never get the tension right, ever. Awesome sounding machine though, definitley worth dealing with it when it was all I had. I wish I could help you more, but when my machine got to that point I put my foot down and bought a 1200.

dave

 

[bradzatitagain]

[quote author="sverige_cruz"]Thanks, Dave -

I'm currently on that list, and been searching the archives...but it's way slow (not to mention there are millions of posts and no way to search all of them...) I've just recently posted there too. My friend has tried talking to a guy at BASE (http://www.analogrules.com/index.html), but he said they're pretty busy to be answering questions via email/phone. We did manage to get a "how to jumper the dummy plug" for the capstan speed reference, though. This thing has been a beast...but we're dying to hear it. Thanks, again!

--Jesus[/quote]

There is a way to search the Ampex list archives, ping Howard Sanner or the guardians of the server, or just post anybody, really, and someone will tell you how. I used to know how, now can't recall or I'd tell you so myself. You can also download the manual and any service updates if you don't already have them, from the recordist site.


WARNING!: The 1100 is not the most revered machine among the regular contributors on the list, you may rcve outright discouragement, but don't let that bother you, somebody will eventually come to your aid. I suggest posting your deck's maladys there just as you posted them here. Somebody there will definitely give you a foot up, but you may have to take a bit of a ribbing. There's probably someone on list who designed the machine, so...

My 2cents: The take up reel should spin when in play, that's what tensions the tape. Try to energize the capstan motor ISOLATED from the circuit--just take it out of the circuit, apply the proper voltage and see if it spins, see if you can jump past the servo too, just energize the motor. If the motor spins it's obviously in the control circuits. The resulting work sounds like a nightmare only a truly dedicated Ampex owner would be willing to cope with. You should also check to make sure all your plug in relays work, no?

Then price an MM1000 or an MM1200.

Steve Puntolillo is selling a 1200 remote, he advertised it on the list. Good price.

rgrds & best of luck,
Brad

 

[sverige_cruz]

Thanks, guys. And thanks for the heads up about possibly getting spat on, after posting about the 1100 on the Ampex list. I don't blame them :wink:

The take up reel should spin when in play, that's what tensions the tape.

- yeah, that makes sense. I don't think I wrote it, but when the tape is on, it's the tape that gets really tight, like the take up reel is pulling, but nothing else is letting it do it. And so on... I didn't think of taking the capstan out of circuit and energizing it. That should eliminate guessing there. It's tough, between the both of us, since I am a newbee in recording gear electronics (or any electronics, for that matter), and my friend just knows how to run it, but I feel with a little (lot) patience, and people's helping hands online, we'll gain some insight on this machine. I've got the op/maint. manual that we've been working off of, but the human-help factor is invaluable. Thanks!

--Jesus

 

[PRR]

Dumb checks:

Does the capstan spin by finger? I don't know that machine, but on most machines the capstan spins "freely", often with large inertia. And I had a fleet of Teacs that, if left idle for a year, the capstan bearing oil would gum-up and the capstan be hard or impossible to spin.

When left in Play, does the capstan motor get warm? Some models get warmer than others, but if it stays stone-cold I would suspect it isn't getting any juice at all. This could be a broken winding, but more likely upstream (connectors, switches, relays, or servo-boards).

In Play, but with the pinch-roller lifted off the capstan, will the take-up motor pull tape from the supply motor? It may need a little help, but if it won't feed even with a finger-push then the supply reel brakes may not be releasing (another fault on old machines when rust gets in the brake solenoids.)

 

[sverige_cruz]

Thank you PRR!

I remember the capstan moving, by hand, but I didn't really try to spin it. Will do.

When left in Play, does the capstan motor get warm?

Another "will check". All I know for now is that the control box goes dark, but we'll check it out.

In Play, but with the pinch-roller lifted off the capstan...

The pinch roller does not touch the capstan, while doing any of the things we've tried. BUT - it's sounds like you said; that the supply reel brakes are not releasing. I don't remember, but "I think" Bo Hansen had put his 2 cents in previously, about it maybe being the solenoids...could be wrong, though. Back to the beast...Thanks!

--Jesus

 

[Bo Hansen]

Hi Jesus,

After this weekend on monday when I are in my workshop again, I will take a look in the MM-1100 manual and see if I can find out something that can help you you.

--Bo

 

[sverige_cruz]

SCHYST!

Tack så mycket!!

--Jesus

 

[bradzatitagain]

Here's how to search the Ampex archive:


http://stuff.jkc-lab.com/ampex/archive/
username: your email address
password: ampex-list

Then click on the SEARCH link at the top of that page, re-enter username and password and you'll get a page with search fields.

Think of this deck as a beautiful old Mercedes you just bought last week but hasn't been started in 20 years. Read the whole manual, top to bottom, side to side. Then read it again. It's a pretty complicated machine. Be patieint. Best of luck, Jesus, let us know how things go.

rgrds,
Brad

 

[Bo Hansen]

Jesus,

The first thing you must do is to check that you have the +5 volt logic rail from the power supply. (you say that the 15v, 27v and 39v is ok but you have not talk about the +5v)

This +5 volt is very important because this is the voltage supply for the logic IC on the transport and capstan PWA cards.

You can measure this voltage on the main power supply the J1 connector between pin pin 7 (+5v) and pin 8 (common 5v)
If you not have 5 volt here, check the fuse F5 or the 5 volt regulator LM-309-K.

--Bo

 

[Bluzzi]

I have a bit of experience with a MM1000 (we still have ot but its not being used anymore).

I am not sure if the transport is similar to MM1000 but I know we had to adjust the air-caps beside the reel motors and brakes.

Your capstan I don't know about as I think the MM1100 is not same there.

If you have relays check that they are all working. Check which ones are f or what and have someone run the transport while you look at them to see if they actually engage and hold. On the MM1000 some relays engage only to to engage another relay then turn off. In other words the second relay was deoending on the first one to turn on momentarily. This was one of the problems we had that we solved.

Another problem we had was that some of the relays are timed by capacitors and th ecapacitors had strayed quite a bit from their original value. Replacing them solved that. Another one was a bad contact on one of the transport switches.

The machine runs well but its just dormant now. A huge behemoth of 16 tracks. I am supposed to sell for my friend but he such a procrastinator it will be a while before it gets put on eBay.

Try and find a local tech maybe that has experience or a good sense (instinct) for these old machines. I had 2 supposed experienced audio techs look at it without a clue until I asked a friend of mine that is an electronics genius to look at it. After explaining and working with him we were able to arrive at solving problems. So your input is very valuable in order to arrive at a conclusion. Some techs will not want to hear your opinions. Keep telling them as you may have a better idea then them because you are on that machine a lot longer.

Also I remember also getting on the Ampex list when we had problems. Some are extremely knowledgeable and although may not have the answer for you may point you to someone that does! (if there are still the same bunch there).

Anyway good luck to you man. I have been through that and I know how it is when we have a dream and it starts to haunt us.

Jim

 

[sverige_cruz]

Thanks to both Bo and Jim. So far, in such a remarkably short time, I've heard suggestions from quite a few people. People on this forum are great! Too bad the outside world ain't as giving and forgiving. Well, thanks!

Bo,

This +5 volt is very important because this is the voltage supply for the logic IC on the transport and capstan PWA cards.

We'll have a look in a couple days, or the weekend. My friend teaches high school, so he's eaither busy, or dead during the week. I'll keep you posted.

Jim, thanks for the suggestions. I ain't giving up yet.

Best Regards,
Jesus

 

[sverige_cruz]

update #1

Just an update of our troubles, in case anyone has any suggestions, or epiphanies:

- tried out the capstan motor with a 5V power supply: spins nicely

- measured all voltages, even when take up reel spins wildly by itself to the point of no return: all voltages are fine, no dropouts, or nothing. Got +39, +27, +15, and the logic's +5

- noticed something new: when 'end of tape' arm is rotated to simulate tape being there, the motion sensor switch (under the supply reel) engages SW1, which goes to the transport control board. It takes several seconds, though, as the assembly slowly rotates to touch the switch. This leads me to believe that the springs for the brakes(?) is not set up for the appropriate tension. I don't know if engaging these switches is normal, for STOP mode. Nor do I understand the logic circuitry involved when this switch is engaged.

- the take up reel will spin, uncontrollably (and stop only when the 'end of tape' arm is released to its normal 'no-tape' position) under the following conditions:
1. stop mode; rewind button engaged (supply reel spins/stops ok); stop button pressed; take up reel begins to spin
2. stop mode; fast forward button pressed; take up reel spins; stop button pressed; take up reel still spins
3. stop mode; play pressed; take up reel spins; stop button pressed; take up reel still spins

- the capstan still doesn't spin, nor does the pinch roller engage

- the supply reel creeps in stop mode, despite turning the trimpots

- the take up reel not only creeps in stop mode...it gains momentum and starts hauling...

Man! Anybody know of a tech in the southern california area? The only problem with that, is that we don't have much money to spend (hence our attempt to source the villianous creature causing the problems to begin with); and, hearing about the rates of some techs makes us cringe... what's a poor guy to do? Maybe there is some Ampex saint out there waiting to chime in, when all fails (like it hasn't already) :roll: Or maybe someone knows of a telephone-tech, if such things exist.

My friend, who owns the machine, said that BASE, up in Frisco has used transport cards for 200-something. Anyone got a spare they'd like to donate, if only for testing, to see if it's worth buying one? Might as well ask - can't hurt. We'd probably have to get one anyhow, as we can't get the thing to hold still in stop mode.

Well, thanks again, for any and all help. If something miraculous happens, I'll post back.

Best Regards,
Jesus

 

[PRR]

If this were a Crown, I'd say the relays are sticking. Does a 1100 have relays?

I'm not sure why moving the tape guide/sense lever does not instantly hit the switch. In my (non-1100) experience, the lever and switch-cam are screwed together as a solid rotating part. Maybe the 1100 is more sophisticated than me, but maybe it is broke.

 

[bradzatitagain]

Jesus, you guys have a manual, right? & PRR there are relays a plenty, there are two plug ins on the back of each electronics IIRC and I don't know exactly how many are in the transport assembly itself. But anyway, Jesus, I made a broad appeal for a scan of a manual unless you've got one, I'll call it off. Let me know.

 

[sverige_cruz]

Hey guys,

Thanks for the manual request, Brad. I have a partial manual, and of the scans that are there, several are difficult/impossible to read (usually the ones I want to see...of course) As far as the Motion Sense Assembly, PRR, I don't know. On the page of the manual for this mechanism, it states that there is some kind of silicone compound fluid, filled to a certain level. If I get a chance, maybe I can scan it and post it, to aid in the description.
Oh yes - as far as relays go, the only ones I see in the schematics are located on the audio switching boards, but don't seem to have anything to do with the reel setup...er...right?

My friend told me he had a dream about the machine, and that somehow he knew that the crystal was bad...last time I'll use the word "epiphany" in my emails. :grin:

Thanks, again, for taking a look.
--Jesus

 

[bradzatitagain]

[quote author="sverige_cruz"]Hey guys,

Thanks for the manual request, Brad. I have a partial manual, and of the scans that are there, several are difficult/impossible to read.
--Jesus[/quote]

:shock: Download the 1200 manual from the recordist.com site there is at least some info useful to you there. If it's just schematics, well then, I'd be wrong. There is no 1100 manual as I've discovered recently. If you don't have a "Theory of Operation" section in your tattered manual and if there isn't one in the 1200 manual read it in the 440B or 440C manual. You might also gleen *some* useful information in the 440-8 manual T.O.Operation chapter but I'm not promising anything. It will explain the functions of the relays. I think you're missing a few on the transport, Jesus. There are the obvious ones on the electronics/channels.

Brake tensions are pro'ly adjusted at the large adjustable resistors. The tensions are of course different in Play/Record than they would be in Stop/Edit, they're much lighter in edit so you don't snap or stretch tape.

Get a complete manual before you think you'll be able to fix the machine. There are parts and suppliers links at the recordist site and you'll occasionally find manuals on eBay. You really can't make much headway without the maintenance data.

rgrds,
Brad

 

[bradzatitagain]

More hints, if you're having logic and tension problems this may help you guys out, this is from Alistair Heaslett:

I guess I reacted to your statement
that the MM1100 was a dog. Certainly in engineering we knew what was wrong and
it was not the fundamental design. The big problem was that the "per channel "
motherboard that the 440 cards plugged into, was made with a cheaper grade of
fibreglass board, " to save cost". Unfortunately the fiberglass was
hygroscopic. i.e. it absorbed moisture like there was no tomorrow. The result
was noise, stray logic misfires etc etc.

I went out into the field once, to a studio farm near Nashville. There we
stripped all the motherboards out of 2 MM1100's, unplugged all the relays,
and washed the water & moisture out/off the PC boards with the help of a
bucket of isopropyl alchohol and then baked them dry in the electric oven of
the farmhouse kitchen. Once this was done we masked appropriate places and
spray coated the boards with lacquer. No problems after that!!

The other problems with the MM1100 included unsealed relays which developed
rapid contact contamination from 'pot' smoke which would gather in the back
of the bays! This would result in bad record/repro/sync switching. Also
serious tension drift due to the effect of AC line voltage variations
affecting the tension servo! All of these problems were addressed in the
redesign of the motherboard and other areas in the MM1200. The fundamental,
design of the transport etc did not change with the MM1200, we just fixed the
bad stuff!

Jerry Hertell's comments:

I used to work in printed circuit board fabrication, so let me add a couple of things to Alastair Heaslett's "fix" for moisture in pwb's. The fix, as he describes is fundamentally:

1) get moisture out
2) try to keep it from getting back in

Additional points:

a) when cleaning, be sure to remove any excess soldering residue between traces or pads. (Rationale - rosin provides a place/pathway for moisture to accumulate

b) after baking, let the board cool in a dry atmosphere (e.g. a sealed container with desiccant in it. (Rationale - to prevent moisture from the air being re-absorbed, while the board cools)

c) when coating the board, be sure to coat the edges and the insides of any holes, which are bare. (rationale - to prevent moisture from "wicking" along the edges of glass fibers, which are exposed on the edges, including holes) We would often coat the edges of pwb's with the same epoxy used for solder-mask.

And, get the manual.
:wink: