Tandberg 12-4 Reel to Reel - what's wrong?

I wonder if anyone could advise me as to what I might do about the faults on a recently purchased Tandberg 12-4. It is cosmetically in excellent condition but although it will FastForward and Rewind, it will not Play in 1+7/8 or 3+3/4. It will Playback in 7+1/2 however but it looks to me like the actual speed is 3+3/4 but then it's a long time since I have watched open reel tape spinning around! Before I try and investigate myself (I am NOT an expert) or give it to someone else to look at, I wondered if anyone had any ideas? I would like to have a go at doing it myself but it depends how complex the fix would be.
The Auto-Shut off also doesn't work but that is less of an issue.
Many thanks in advance for considering this. It is lovely to get my hands on this machine which I used extensively in my role as a music teacher in the early 1970's. It was a joy to use!
Cheers
PS. I have a copy of the service manual.

 

Sounds like a speed-changing idler wheel is not moving into position... most likely because the lubricants have turned to thick sludge. It needs to be opened up for a good cleaning and re-lube. Typical for old reel-to-reel machines now.

 

Thanks so much for speedy reply. I will examine the manual and summon up courage!
Do you have any thoughts re. the Auto Shut Off?

 

The mechanisms, transport parts and adjustments are complicated. So is the disassembly and cleaning. Got to HiFiEngine here, to register for free and download the service manual.

 

Sorry, but not being familiar with this machine, I don't know what mechanism Teac used for Auto Shut-Off. Is it one of the guide arms (to one side) that drops when the tape runs out? Are they "frozen" or do they move freely? The manual would tell you where the Auto Shut-Off is.

 

Thanks Agitater and Wes H. I have looked at the manual but am wondering if I need an idiots guide as it shows all the detail but not how to do it.
Perhaps I need to look out for a scrap model to buy and experiment on? The Auto Shut Off is indicated in the guide but it's hard to match up what it
shows to what is on the machine itself. And it's a Tandberg not a Teac by the way! A guy who fixed vintage hifi I found near Leigh on the A580 ( so
not a million miles away from me) has replied to my enquiry to look at it with the message that he doesn't do reel to reel any more and, no, he doesn't know anyone who does in the North of England. Hmmmmm.......

 

There has to be someone experienced and reliable in Manchester. If not there, then in Liverpool or Leeds.

Talk to the local or regional audio shop owners because it's likely that one or more of them will know who does the sort of service you need.

 

Yes, Tandberg! Sorry.
Service manuals are not "how to" manuals for owners. They just show you where everything is located and how to make fine adjustments and alignments. They assume you have some technical background or experience. If you're not mechanically inclined or have any experience taking things like this apart, then (as Agitater suggests) you really should find someone who can help you with it.
That said, I took a quick look at the service manual and it seems the Auto Shut-Off pin rides on the tape just ahead of the last (far right) tape guide. So I see four possibilities:
1. It appears that there is some sort of hooked plate (like a backwards "J") next to it which, I suspect, the pin might be getting caught on.
2. Or, it could be designed that way, so the user can clip the Auto Shut-Off pin inside that "J" plate to keep it from contacting the tape (defeating the Auto Shut-Off).
3. Perhaps the grease this pin rides in (to dampen its action) has hardened and the pin is stuck. This, however, is unusual (in my experience) -- as the pin is often stuck in the "off" position. Was the machine stored for years with tape loaded (threaded) on it?...that's the only way I can see it being stuck open.
4. The pin has broken off and the Auto Shut-Off is jammed in the "on" position.

Take a look. If you still can't figure it out, then post a picture of it so I can see.
You'll still need to get inside this machine to clean and re-lube, if you want the speed control to work.

 

The speed problem will be obvious when stripped down. The stepped rubber wheel will be seized somewhere.
With the machine on stop when you press down forward wind control the right spool should be able to move to the right it may need help. With a few movements back and fourth it will ease back to life.
Lubrication ,is all thsts required.
The auto shut down is easy .
tanberg tape and some EMI had a piece of chrome ( shiney and silver) tape on the end of the tape. When the chrome tape made contact with the contact the machine stopped.

 

You mean it is designed to sense auto-reversing foil in the tape path for auto shut-off? I didn't see anything like that in the service manual schematic...

 

I write from memory. Had a few tape machines. Your model may differ from
Mine.
An old sony i had had a sensing device thst was lightly spring loaded. When tape ran out it would fully extend and stop.
Sorry, I cannot recall anything else, useful, I was tape recorder mad for many years.The Tandberg was the most stunning machine i ever saw and used.

 

Yes, from what I can see in the fuzzy service manual I downloaded, the Norwegians did things a bit differently from the Japanese... So who knows? Maybe they built a better mouse trap.