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Vintage Tape (Audio), Cassette, Wire and Magnetic Disc Recorders and Players Open-reel tape recorders, cassette recorders, 8-track players etc.

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Old 23rd Oct 2022, 7:06 pm   #41
DMcMahon
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Default Re: Tandberg AT 771 Portable Mono Cassette Recorder

I found my book but it is not the JVC Service Guide but a National Panasonic Technical Guide, somewhat similar to the JVC guide but with more information, it describes 5 variants of the Auto Stop mechanism.

David
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Old 24th Oct 2022, 1:58 pm   #42
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Default Re: Tandberg AT 771 Portable Mono Cassette Recorder

Tested the Auto Stop operation during Play and Record and it works very well, quite a forceful unlatching of the respective keys.

With the cassette door removed, could see that when the tape stops moving the tape tension increases and it becomes taut, which makes the white peg (auto stop lever / detect cap) to then move / spring up and the latched Play or Play & Record keys are subsequently unlatched.

With the PCB lifted up so that the underside of the tape mechanism could be seen tried to see how the white peg moving actually caused the keys to unlatch but could not really see without removing parts. Could not see the underside of the flywheel to see if it had the pin or pawl that is part of the process.

David
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Old 24th Oct 2022, 2:35 pm   #43
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Default Re: Tandberg AT 771 Portable Mono Cassette Recorder

Repaired the broken tape counter reset button by gluing a piece on. There was not much left to glue onto and unfortunately the new piece does not sit central in the cut-out but at least it works.

Tested internal microphone recording which works well, this is automatic record level, i.e. no manual control over the record level

Tested line recording into the Line In DIN connector, this works well, with the record level being manually adjusted by the Ext.Mic.Volume control.

Even though it records well and plenty of good quality volume on playback, the record level may be a bit down, even with the Ext.Mic.Volume (record level) at maximum, the VU meter seldom gets to 0VU even on loud music peaks. The volume of the recorded music is lower than a prerecorded music cassette or a cassette recorded on another machine.

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Old 24th Oct 2022, 7:19 pm   #44
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Default Re: Tandberg AT 771 Portable Mono Cassette Recorder

Connected one of my JPW Gold Monitor bookshelf speakers (8 Ohm) to test external speaker operation, these speakers sound very good when connected to Hi-Fi amp.

The sound was different compared to internal speaker (6 Ohm) operation with more noticeable bass on the JPW and brighter on internal speaker, difficult to say which sounded best, maybe the JPW but internal speaker operation is still very good sound.

Checking out a small problem with the cassette ejection, when cassette is ejected the cassette door opens but only around 2/3, can remove cassette but a bit tight.

Manually pulling the door to the fully open position shows the door is quite stiff and noisy during the remaining 1/3 opening.

Lubricating the plastic hinge pins at the bottom of the door made no difference. Above the hinge pins are 2 black rubber sleeves/buffers (that fit onto stubs on the door), the end of these make contact with 2 plastic ramps (ramps are part of the plastic case). By removing both rubber buffers the door then flies open at speed, fitting just one of the rubber buffers results in improved operation but still not good. Lubricating the rubber buffers made a very minor improvement.

So it looks like the function of the rubber buffers is to dampen the opening speed.

Think I need to try either slicing a narrow piece off the end of the rubber buffers or sandpaper them down, the ends are quite hard and you can hear/feel them rub when making contact with the ramps.

David
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Old 24th Oct 2022, 11:07 pm   #45
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Default Re: Tandberg AT 771 Portable Mono Cassette Recorder

After using a flat needle file to remove some of the hard rubber from the ends of the rubber buffers, the cassette door is now working a lot better.

David
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Old 21st Nov 2022, 11:12 pm   #46
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Default Re: Tandberg AT 771 Portable Mono Cassette Recorder

Did external microphone recording test, this microphone also has the Remote connector with on/off switch for remote control. The remote control and the microphone worked very well. I have 2 of these microphones, they have no identification markings, unsure where they came from, they maybe are the microphones that came with my Akai 1800 accessories kit ?

The only thing left to test is the DIN line output. I was thinking of selling it but I think I will keep it as it is very nice indeed and lovely sound.

David
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Old 22nd Nov 2022, 10:14 am   #47
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Default Re: Tandberg AT 771 Portable Mono Cassette Recorder

The microphones are definitely not the Akai ones as can be seen in Post 4 of this link

https://www.vintage-radio.net/forum/...d.php?t=189745

Next guess is that they came with a small Sony R2R.

David
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Old 23rd Nov 2022, 2:01 pm   #48
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Default Re: Tandberg AT 771 Portable Mono Cassette Recorder

Round here the Tandberg reel to reels in their grey cabinets seemed to be the standard schools machine. Presumably the machine under discussion was an attempt to hold onto that market as it switched to cassette. My primary school also had an R2R made by Coomber or similar, possibly based on the cheap Truvox deck, but the Tandberg was always their first choice.

JVC and Panasonic (Matshushita) used to have financial links so it's not surprising there seems to be some cross fertilisation.
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Old 23rd Nov 2022, 2:19 pm   #49
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Default Re: Tandberg AT 771 Portable Mono Cassette Recorder

Our primary school had those grey Tandberg R-Rs plus lots of mid-70s Philips cassette machines, predominantly the one with the pop-out microphone, seems to be the N2225: https://storycase.co.uk/radio/tape-r...ette-recorder/

Unsurprisingly, only the Tandbergs got used when an entire class had to listen. The cassette machines' amps/speakers were too feeble.
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Old 23rd Nov 2022, 3:20 pm   #50
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Default Re: Tandberg AT 771 Portable Mono Cassette Recorder

Same here Nick, though I don't recall seeing a reel to reel in primary. Plenty of Coomber units like the 343 with their beefy speakers. There was also a Hacker GP42 on a trolley with the separate speaker below.

Secondary school was Tandberg series 15s (which I ended up maintaining), some of the aforementioned Coombers (and a few newer ones) and a few of those N2225s. You are right about the lack of volume! I remember using the 2225s in drama classes and the recording quality was excellent.

Didn't see any of the AT771 cassette units though.
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Old 24th Nov 2022, 11:34 am   #51
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Default Re: Tandberg AT 771 Portable Mono Cassette Recorder

I bet your heart rate must have leapt upon seeing 'Tandberg' on that recorder.
When I saw the photograph it looked like the company had taken a standard radio-cassette deck shell and blanked out the space for the tuning scale.
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Old 28th Nov 2022, 12:05 am   #52
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Default Re: Tandberg AT 771 Portable Mono Cassette Recorder

Because there's no radio section these seem to be rather cheap. I scored one for twenty quid.
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Old 1st Dec 2022, 7:08 pm   #53
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Default Re: Tandberg AT 771 Portable Mono Cassette Recorder

Audio power is more than enough to be loud & obnoxious. No wonder people carried these around on their shoulders with the vast amount of 'D' cells they needed. The Tandberg wants six, which is around seven pounds approx. Goodness knows how long they'd last.
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Old 1st Dec 2022, 8:43 pm   #54
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Default Re: Tandberg AT 771 Portable Mono Cassette Recorder

It runs fine on batteries, but I have only run it on batteries for short periods so no idea about useable battery life.

David
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Old 2nd Dec 2022, 8:59 am   #55
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Default Re: Tandberg AT 771 Portable Mono Cassette Recorder

You used to be able to get a hand-cranked fast winder accessory to save wear & tear on the tape transport and extend battery life. That's a useful accessory, if you are out & about.

I think some patch cables ought to be my next consideration. I can make them up.
But what is the pin arrangement in the DIN plug? I assume Left & Right in & out with the metal shield to the screening of the cable.
Don't know which pins are which.
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Old 2nd Dec 2022, 11:40 am   #56
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Default Re: Tandberg AT 771 Portable Mono Cassette Recorder

Standard DIN pin out for a tape machine is inputs on pins 1 & 4, outputs on pins 3 and 5, pin 2 being the screen connection.

As the AT 771 is mono it is possible that they link pin 1 to 4 and link pin 3 to 5, I need to check on the 771 to see.

David
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Old 5th Dec 2022, 3:32 pm   #57
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Default Re: Tandberg AT 771 Portable Mono Cassette Recorder

By resistance measurement at the 4 phono plugs of a phono to 5 pin DIN cable, with cable connected to the AT 771 Line In/Line Out DIN shows that pins 1 & 4 are linked together and also pins 3 & 5 are linked together.

David
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Old 7th Dec 2022, 10:53 pm   #58
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Default Re: Tandberg AT 771 Portable Mono Cassette Recorder

Did the final outstanding test of line out (to Hi-Fi amp tape in) playback, sound was very good.

David

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