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Topic: Ampex AG-440 Tape Deck... Need info.

Bruce McGee
Phenomenal Film Handler

Posts: 1776
From: Asheville, NC USA... Nowhere in Particular.
Registered: Aug 1999

posted 11-05-2001 09:47 AM

SUCK-UP TIME:

Please dont kill me for posting this here, but I know of no other place with a better group of trustworthy electronics-types on the net.

I rescued the AG-440 from the junk heap, along with a like-new ReVox deck. The ReVox is working fine, after some cleaning/lubricating. The 440 hasblown the 1/2 amp fuse on the power supply unit under the deck control buttons. Just after this fuse is a big wirewound resistor that has overheated, and is checking OK, but 200 ohms higher than the rating.

Before I got it, someone tried the old "Lets put in a bigger fuse and see what happens" trick that I love so. There was a 3 amp-er in there, unblown. The big resistor glows cherry red. but I only saw that once!

The fuse controls the brake operations, and the pinch roller.

It still blows the fuse after all of the solenoids, etc, are unplugged from the power supply, so I know the problem is inside.

There are tons of diodes in this machine. I dont want to just start cutting wires to test all of them.

Has anybody got a schematic of the control circuits on this machine? If you need more info, just email me and I will get it pronto.

I COULD NOT let this machine just go to the dump. It is beautiful!!!

What a piece of workmanship!

PLUS I have lots of 10" reel-to-reel tapes (half-track) that will love to be run on this machine. The ReVox is a half-track, too.

As usual, I appreciate all of you, even Joe R.

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Jerry Chase
Phenomenal Film Handler

Posts: 1068
From: Margate, FL, USA
Registered: Nov 2000

posted 11-05-2001 01:03 PM

Have fun:
http://recordist.com/ampex/apxschem.html

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Bruce McGee
Phenomenal Film Handler

Posts: 1776
From: Asheville, NC USA... Nowhere in Particular.
Registered: Aug 1999

posted 11-06-2001 01:58 AM

Jerry, THANKS!!

This site is so big, that I need to go log on at work and access it. WebTV couldn't cut it. Thanks A Million.

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Jerry Chase
Phenomenal Film Handler

Posts: 1068
From: Margate, FL, USA
Registered: Nov 2000

posted 11-06-2001 10:47 AM

Glad to help. I used to think the Ampex decks at my dad's radio station were the coolest things. Then I went with him to see the custom McCurdy equipment installation at the CBC in the late 1950s. Awwww jeeze. Take a kid and show him a starship bridge. Then make him go home.

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99

posted 11-07-2001 04:04 PM

I just recently sold off my Studer A-80 2 track. It went of all places.....to Alaska. I replaced it with a Technics Closed loop RS 1500 that I got at an estate sale for 30 bucks. The Technics has an amazing servo system, even better than the Studer had.......
Mark @ GTS

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Bruce McGee
Phenomenal Film Handler

Posts: 1776
From: Asheville, NC USA... Nowhere in Particular.
Registered: Aug 1999

posted 11-08-2001 12:28 PM

Mark:

Our company has a couple of those closed loop Technics machines. They've been through hell, but continue to run like a dream.

I attempted to run the big Recordist site that Jerry sent me last night at work. I had some trouble, so I'll get with the computer guru and work it out. The AG-440 is just screaming for service and will NOT go to the dump.

I let the electronics on it cook for 6 hours last night. Everything had a musty smell for awhile, but it went away. Now, the bias levels on the meters is exactly the same with no adjustments... before, there was a big difference. All the motors and pivots on the deck are clean and lubed. It's going to work... I can feel it in my bones!

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99

posted 11-08-2001 08:01 PM

Bruce,
Keep at it! There's no reason it should not work. If you do a rebuild consider using MIT multi-caps (type ppmxf) when you replace the coupling caps. They are the best I've found, but be prepared to spend about 15 bucks a cap. Also replace the power supply electrolytics and bypass them with film caps of about .05mfd. This will efffectively lower the power supply impedence quite a bit and will help lower noise floor even more. To make the rebuild even cooler you could use all film caps in the power supply and forget the electrolytics all together!!
Check out Bob Katz's web site and look at the old Ampex MR-70 electronics that he uses. Its among the last Ampex tube stuff built and even has regulated B+ supplies in it. The stuff's amazing!
His web site is www.digido.com
Have fun!
Mark @ GTS

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Josh Jones
Redhat

Posts: 1207
From: Plano, TX
Registered: Apr 2000

posted 11-09-2001 12:30 AM

I also need help getting a Akai 280D-SS running. it had a control card failure as far as I can tell. please help, this machine sounded great for the few hours it did work. I first got it to run by tapping the control card with a screw driver, but it quit. It is a quad machine, runs great, or did. a control board schematic would be of great help.

Josh

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Jerry Chase
Phenomenal Film Handler

Posts: 1068
From: Margate, FL, USA
Registered: Nov 2000

posted 11-09-2001 09:00 AM

Josh, jgl6008@juno.com has a spec sheet and user manual he is willing to copy for a few bucks.

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Bruce McGee
Phenomenal Film Handler

Posts: 1776
From: Asheville, NC USA... Nowhere in Particular.
Registered: Aug 1999

posted 11-09-2001 11:10 AM

Josh: I used to have a 280D!

Try this

Look for cracks in the solder on the control board. You may find some bad soldering too. Mine had a few bad connections, but never messed up after the repairs that I did on the board.

I missed the Guru yesterday. Plus, the Ampex site was down for awhile.

Mark: I was thinking about at least replacing the electrolytics in the power supply for now. The pre-amps will be a more involved project, as you know.

They tell me at work that this Ampex has been in storage for about 5 years in a dry place, and that it quit working a few days before it was to be replaced anyway.

That 3 amp fuse didn't help matters. I've found a 25w wirewound resistor of the same ohms rating as the one that smoked in my junk boxes. I have a feeling that even though the old one still works, the B+ wont be right. This is the 115v DC source. I got this much from the Ampex site that Jerry turned me on to...

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Paul G. Thompson
The Weenie Man

Posts: 4718
From: Mount Vernon WA USA
Registered: Nov 2000

posted 11-12-2001 11:14 PM

Bruce, I'll have to check for sure, but I might have some bones that will fit your machine laying around in the radio station junk. I'll email you if I do.

Paul

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Bruce McGee
Phenomenal Film Handler

Posts: 1776
From: Asheville, NC USA... Nowhere in Particular.
Registered: Aug 1999

posted 11-13-2001 10:27 AM

Thanks, Paul.

Jerry: I'm on the mailing list for the Ampex site. I'm just reading for now. Some of these guys on the list are the designers of the AG-440, and others! I need to compose a really good email to send so I won't look like a spaz. Someone was looking for the "ready" and "record" lamps for a 440... They told him to convert to LED's...

Remember how I do things: On A Budget.

I'd like to find a paper service manual somewhere. I never liked microfilm copies of schematics.

(I KNEW that there would be some magnetic tape-types here at Film-Tech!)

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Jerry Chase
Phenomenal Film Handler

Posts: 1068
From: Margate, FL, USA
Registered: Nov 2000

posted 11-13-2001 10:26 PM

"I'm on the mailing list for the Ampex site. I'm just reading for now. Some of these guys on the list are the designers of the AG-440, and others!"

Cool. Tell them they have admirers.

Now if the old electronic junk shops on Canal street in NYC would just re-open with all the stuff they used to have...

I snagged a lot of fixable stuff out of those bins. Turntable, a couple of amps, tons of early circuit board parts, all MIL spec. Most of the stuff I made didn't work or worked poorly, but it was fun and cheap to play around.

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Josh Jones
Redhat

Posts: 1207
From: Plano, TX
Registered: Apr 2000

posted 11-13-2001 11:29 PM

well, I e-mailed that guy. I checked the board and couldnt find any broken traces. when the control buttons are pushed the relays dont even fire. It's probably something simple, but I wish I knew what it was.

Josh

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Paul G. Thompson
The Weenie Man

Posts: 4718
From: Mount Vernon WA USA
Registered: Nov 2000

posted 11-14-2001 01:26 AM

Josh, check the relay armature rail supply to see if it even exists. Could be you may have a fried diode in a power supply. If nothing works, I would certainly suspect the control logic board or the power supply. If you get a roadmap on that critter, you and I will have that thing running very soon.

Paul

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