Ever see an ampex atr102 capstan spin violently fast without tape loaded?

[pucho812]

Fired up the atr 102 today and the capstan is taking off with no tape loaded. It spins fast.
I don’t recall this as normal ampex behavior .

 

[Brian Roth]

Pull out the Capstan servo card (power off of course) far enough out so it doesn't make contact with the edge connector, then power up and see what happens. If it continues to run away, most likely a bad power transistor driving the motor. If no wild spinning, then fault on the capstan card or the opto assembly on the glass disc at the motor itself needs to be mechanically adjusted.

Bri

 

[pucho812]

Pull out the Capstan servo card (power off of course) far enough out so it doesn't make contact with the edge connector, then power up and see what happens. If it continues to run away, most likely a bad power transistor driving the motor. If no wild spinning, then fault on the capstan card or the opto assembly on the glass disc at the motor itself needs to be mechanically adjusted.

Bri

I will check that out today and see. thanks Brian.

 

[pucho812]

Capstan servo card when pulled, causes the capstan to not rocket with no tape on.

Time to redo my cards, for transport and the rest, the machine is due

 

[Brian Roth]

In the Ampex manual (I don't have one here at home) there is a procedure for adjusting the opto device that reads the glass disk on the capstan motor. IIRC, a misalignment of that opto can cause a runaway.

If you can find a second (known to be working) capstan card, that can help see if it's that PCB or something else.

Bri

 

[pucho812]

In the Ampex manual (I don't have one here at home) there is a procedure for adjusting the opto device that reads the glass disk on the capstan motor. IIRC, a misalignment of that opto can cause a runaway.

If you can find a second (known to be working) capstan card, that can help see if it's that PCB or something else.

Bri

I have a manual, I need to go through the machine. It has not been in use for sometime and like most studio equipment around here, did not see any servicing prior to my arrival which was a good 10 years of no techs at all. to further complicate the issues any known good gear was sold off so a lot of the working stuff has left the building. But we are fighting the good fight, this is next, they are good machines and sound great when in order.

 

[Brian Roth]

Even before I moved to Salina in 2014, I was making regular "house calls" to Blue Heaven Studios which had a pair of ATR-102's. I seldom had any Ampex probs on the work list. Main projects always involved the Neve desk.

Now we have eight ATRs and they are pretty damned reliable.....especially considering the ATR decks were made from mid 1970's into mid 80's. But they are 40-ish years old now and odd quirks arise. I have been working on stockpiling spare parts to keep the "fleet" running. ATR Services in PA is a great resource for odd items, and I also watch Ebay.

In these days, it seems one machine is offline due to a fault at any given day/month. It's "Brian's whack-a mole" at times! LOL But, I really have no major beefs. Those machines were built "when men were men and the sheep were nervous"......apologies for that! lol

I currently have one machine "semi down" since the bias signal from the master audio control card is not working....although erase is OK. We shuffled the machines around so that one is used only for playback during the making of Ultra Tapes. Once we get through the run of many titles (I was told 800 10.5" reels of 1/4"....we are the largest customer of RMG tape in the world) , I'll dig back in again.

Bri

 

[musgrave]

The 2N3055's under the black top covers. the MDA's motor drive amps. they will spin a reel or capstan when they go. pull the card and if it spin's the motor still, is a typical symptom easy job if that's it. be careful when removing transistors screws, don't push the sockets out of the backside, or when pushing new part in. you would need to remove the rack with the allen bolts on the top deck under the black deck covers. easy too, if you have a rolling frame, lock it in so the deck is upside down, without grey outer cover on. then just lift power, and rack out separately. I replace with beefier T03's 2n3055 style parts.in pairs per motor