Aiwa F770 cassette from 1985

the

REW

the

control

pinchwheel

I think its an ADF 770. Could it be a 3 head model?

one that can replay the tape while it is being recorded ?

fighting

back

pinch

Yes F770 on the front and AD F770 on the back. Yes 3 head , presumably one erase head and one double head, 2 motors. why would someone need to replay at record - some semi-pro facility for EQ checks ?

Sounds like a quality cassette deck.

2 pinchwheels are used to pull the tape taut as it passes over the heads. The reuslt is a dramatic increase in reliability of tape to head contact, thus eliminating a common cause of poor quality sound.

4 heads are used so that one can listen to the played back signal during recording. This enables several things:

1. you can adjust the bias and hear the result almost instantly, which makes a quality improvement with many tapes
2. If there is muck on the head, a bad tape, incomplete erase, or any other recording problem, you know immediately, and dont waste a lot of time making a dud recording.

Sounds like its well worth fixing.

As for the pinchwheel protrusion, I dont know what it looks like so its impossible to say. Peraps its a small protrusion designed to hold the cassette in exactly the right position, cheaper decks often dont have accurate cassette shell holding, with predictable inconsistent results on tape to head contact and alignment.

PS all this technology goes back to the 70s, there was a late 70s Pioneer that had all the above, and is/was still one of the best cassetts decks 20 years later.

NT

"N Cook" wrote in news:esk4bk$76s$ snipped-for-privacy@inews.gazeta.pl:

Could it be an auto reverse deck that reverses when it hits a metal band or transparent area of the tape, near the end of the reel?

One set of heads plays/records in one direction and the other set plays/records in the other direction?

I seem to remember Aiwa had some like that. My shop used to work on them in the early 70's (back when I had a shop).

The strange guide could be a 'tape tension' sensor. It may have been disabled at some time in the past to fix some problem.

Google shows several "Aiwa F770 Three-Head Studio Quality Cassette Deck" listings, so the chances are that it is to allow 'sound over' recording by playing back and mixing in new audio and then recording that, after the sound that was just played is erased.

One last possiblity, the second pinch roller could be for a second recording speed. I seem to remember some machines that played that trick to allow multi speed recording.

--
bz    	73 de N5BZ k

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an 
infinite set.

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"N Cook" wrote in news:eskc7o$7v8$ snipped-for-privacy@inews.gazeta.pl:

not replay at record. Get the sound currently on the tape off, mix it with some new sound and re-record it.

Les Paul and Mary Ford used to do multi part harmony with just two singers and two guitars by such a method.

--
bz    	73 de N5BZ k

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an 
infinite set.

bz+ser@ch100-5.chem.lsu.edu   remove ch100-5 to avoid spam trap

When you get to this era - not necessarily. If the deck had any bias adjustment control then you needed a three head setup to compare the sound coming off the tape to the source in order to tweak the bias setting to an optimum position for the tape being used. Funny that my TEAC V770 has this option and the model number is so similar to the Awia unit here.

Rick

That was an expensive and desirable feature. You knew immediately if there were problems, such as badly set record gain, dirty heads, tape path problems, etc. etc. Anyone who's ever made an important recording and found out at playback time it didn't work would give his auto-reverse for this feature.

--
        Martians drive SUVs!

the

pinch

control

pinchwheel

EQ

That explains the multiple heads, the protruding tape guide and the free running "pinch wheel" but why a contra-rotating spindle adjascent to it if its not used for any reverse play / review function or any function that i can see ?

or

to

The 2 pinch wheel holders are engaged/disengaged by the same sliding plate so the normal one is engaged against the spindle and the "reverse" one is close to the contra rotating spindle. There is no possibility of the sliding plate to do anything else eg swivel to engage one or the other fully.

The added tape guide is part of the normal swinging mount of a pinch wheel but extending around a part of the curve of the pinch wheel so intruding into the tape path.

I'll take some pics tomorrow and upload somewhere.

or

to

picture with the odd pinch wheel housing on the left, normal one to the right

or

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

"N Cook" wrote in news:eskk7a$dn0$ snipped-for-privacy@inews.gazeta.pl:

Looks like the head has two sets of stereo heads, offset from each other

- -

- -

Which would support the two way supposition.

--
bz    	73 de N5BZ k

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an 
infinite set.

bz+ser@ch100-5.chem.lsu.edu   remove ch100-5 to avoid spam trap

bz ha escrito:

What you have here is a single direction, 3 head tape deck. The capstans should both go the same way. If not, you have a capstan belt on incorrectly. Try it.

BTW, the protrusion on the LH pinch roller is a tape guide to ensure the tape is fed to the pinch/capstan perfectly straight. In some models of more elaborate decks which had both 3 heads AND autoreverse, I'm sure i recall having seen it used as the erase head!

-Ben.

news:eskk7a$dn0$ snipped-for-privacy@inews.gazeta.pl:

the

I had assumed the low-side wow, when i had the springs set wrong, was due to one pinch wheel fighting the other. Perhaps that black plastic tape guide was touching the spindle and breaking the whole train , then. Both capstans in fact do rotate the same way. Surely you can't have 2 flywheels and 2 capstans with pinchwheels engaging the same tape, even if connected by the same rubber band.

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

the extra bit is a tape guide for better tape path control.

absolutely, they must rotate same way

Yes, thats how they work. The one on the left is driven by the one on the right via a belt. Belts are a little lossy since they stretch at one end more than the other, giving a slight speed difference when free running. Put the tape in and this translates to putting tension on the tape. Its a very effective method. Once you've had a deck like this you wont want to go back to the cheaper more common system.

NT

engaging

I put the deck back in the chassis to check speed and record function. If I had not been aware of the features before that i would certainly now on record. It routinely uses playback at record as VU and PPM rather than direct from source. So you set to record a signal and nothing appears on the VUs until the tape has passed from leader to ferrite. Nice to have big numbers etc on a proper large clear and bright cold cathode display.

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

I dont know the Aiwa one, but typically on this type of deck you can switch metering and audio output between record head and play head, so you can run it either way.

NT

'Tape-source' switch, usually.

-B.

belt

on

cathode

Back to the original problem. The belts had dropped off, obviously perished. Now , sometimes, on using the power take off to slide up the head carrier one of the belts drops off. The one that links the 2 flywheels directly together. The first motor to flywheel belt stays on. The second belt is driven by a flat pulley driving a vaguely bulbous pulley. Belt dimensins of width and thickness are much the same as the originals but obviously the length is less than the perished one - try a longer belt ? There may be just enough room to add a disc of plastic to the flywheel to stop it falling off or putting a static guard in place - any ideas?

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

N Cook ha escrito:

I don't understand. have you replaced the belts with new? if so, nothing should be falling off and nothing will need modifying.

-B.