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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 10th Mar 2019, 7:27 pm   #1
19Seventy7
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Default Aiwa F640 - No sound

Hi,

I was given an Aiwa AD F640 3 head cassette deck to restore, which I have, mechanically at least.

When a tape is played, it spins but no sound comes from my speakers, nor does the sound meter light up and show that sound is being recognised.
I connected my radio in, which the meter recognised and lit up. I then tried recording onto a blank tape from the radio, and got no sound either when played on a second tape deck, as it didn’t record.

The heads and capstans and pinch roller have been cleaned, too

What could be the issue? I’m a bit stuck after some fiddeling with no results.

Thanks
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Old 10th Mar 2019, 8:11 pm   #2
Michael Maurice
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Default Re: Aiwa F640 - No sound

Download the manual from hifi engine check the power supply rails.
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Old 10th Mar 2019, 8:56 pm   #3
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Default Re: Aiwa F640 - No sound

Hi,

Thanks for the link, I've had a look at the schematic diagram, but I cannot understand it all that well, unfortunately

Does anyone know what the power rails look like, and what they should measure at?

Thanks
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Old 10th Mar 2019, 10:10 pm   #4
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Default Re: Aiwa F640 - No sound

The power rails are just lines coming out of the power supply and going to different parts of the diagram, You really need to know how to interpret these diagrams.
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Old 10th Mar 2019, 10:21 pm   #5
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Default Re: Aiwa F640 - No sound

Oh okay, thank you.

I really do, what way is recommended to learn, if there is any?

Thanks for your help!
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Old 10th Mar 2019, 10:27 pm   #6
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Default Re: Aiwa F640 - No sound

I cant teach you over the net, it takes practice and even experienced engineers can have difficulty.

in your case, you should start by looking at the record and playback amplifiers and see where the supplies go to. Now measure them, are they the same as in the diagram, if not you need to work out where they come from, if the supplies are ok then you need to input a tone signal and use a scope to find out where its gone missing.
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Old 10th Mar 2019, 11:13 pm   #7
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Default Re: Aiwa F640 - No sound

Just for info, split rail power supplies in the schematic I'm looking at, +-7 volts for the amplifier sections except for the headphone amplifier which is +-15.5 volts (approx.) Bias/erase oscillator is powered from a +10.5 volt rail.

Lawrence.
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Old 10th Mar 2019, 11:16 pm   #8
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Default Re: Aiwa F640 - No sound

This is a nice, sought after cassette unit but it is a complex beast and not easy to work on. I know because I own two of this range which I restored some years ago. It is no place for the novice. The only thing you will do by poking about where you don't understand is turn what may well be a simple fix for a technician with the experience or knowledge into an expensive or irreparable mess.

Please, leave it be and look for someone local to you that might be able to deal with it. Ask in the relevant wanted section on here for starters.

Meanwhile, why not look for a simpler 2 header unit to gain some experience on. There are plenty from the 1990s that can be picked up cheap.

Best of luck.
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Old 10th Mar 2019, 11:17 pm   #9
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Default Re: Aiwa F640 - No sound

I've highlighted the outputs of the deck's PSU. They look to be: +7v, -7v, +5v, +10.5v, +15.5v and -15.7v. All VDC.

Attached is a diagram (sorry for the mess!) to help you understand how you can trace the circuit to find and appropriate point to measure all of the above voltages.

Now it is a matter of understanding where these points are in relation to what is sitting in front of you and measuring them with a DMM.
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Old 10th Mar 2019, 11:52 pm   #10
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Default Re: Aiwa F640 - No sound

That's fair enough and I wouldn't expect anyone to teach me, just tips and tricks, to help, really.

it might take me a while to fix it, but i'll get it up and running - I don't want to rush into it and bodge it up even more

Thank you for your help! It's really appreciated!
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Old 10th Mar 2019, 11:57 pm   #11
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Default Re: Aiwa F640 - No sound

If you get stuck, then please contact me.

Do NOT under any circumstances attempt to adjust any of the presets, it will take some doing to set them up again.
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Old 11th Mar 2019, 12:07 am   #12
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Default Re: Aiwa F640 - No sound

I didn't see all these other replies since Michaels... oops

Ben - I've had many fights with it trying to sort the mechanism out! I'm glad I've finally fixed that after many attempts. When I poke about It's more just looking than any thing else, and usually trying to see what does what.

I got it for free and as I've said, sort the mechanism out, many loose wires and belts which were more like glue. I got it with the plan to do up and move on to someone else once sorted to help me gain experience, help fund my hobby (restoring older tech, even if I am still in the learners stage) and to have a bit of fun with. I'll have a look around for some 2 head decks, too. I would like to be able to fix cassette decks.

OldTechFan96 - Thank you for "That mess" that has cleared things up quite a bit, I now know where to look properly instead of just guessing. I am usually okay with comparing the schematic/diagram to the actual circuitry in front of me, it's just a matter of what's where.

I'll have a look on the proper schematic/diagram now and go from there!

Thank you all for your help! It's very much appreciated!
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Old 11th Mar 2019, 12:11 am   #13
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Default Re: Aiwa F640 - No sound

Quote:
Originally Posted by Michael Maurice View Post
If you get stuck, then please contact me.

Do NOT under any circumstances attempt to adjust any of the presets, it will take some doing to set them up again.
Thank you, I will more than likely need to
I haven't and won't touch anything on the circuit board unless I find it needs to be changed or something - Thanks for the warning

Thanks again
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Old 11th Mar 2019, 9:24 am   #14
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Default Re: Aiwa F640 - No sound

Standard procedure here as in many things in life is to check just one thing at a time. Here don't worry about making new recordings at first. Just see if it will play back a known good (pre recorded) tape.

With a 3 head tape machine, to play back any tape you must have the "source/tape" switch switched to "tape". In "source" you will get no playback.

You report you have "cleaned the heads" but even doing that properly often requires some expertise and the right materials and tools. Are you sure the heads are clean? Have you looked directly at the heads in a good, strong light with a suitable inspection mirror and magnifier?
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Old 11th Mar 2019, 4:28 pm   #15
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Default Re: Aiwa F640 - No sound

I had tried a pre recorded tape before trying to record, but the record was to see if the source made its way to the tape, which it didn't.

I forgot to mention I DID get sound out of it, the night before by plugging it into my VCR into the TV, but the audio wasn’t great, which I didn’t expect it to be. When testing it on proper speakers is when I got no sound.

It was definitely put onto “tape” as it automatically does so, unless changed.

I cleaned the heads using a cotton bud with a dab of isopropyl alcohol. The cotton bud came back clean. I’m not 100% sure the heads are clean, but before I cleaned the heads, there was no sound, when I cleaned them, I got sound. I used my phone torch and had a look to make sure that there was nothing stuck to it like gunk.

Thanks for your help

Last edited by 19Seventy7; 11th Mar 2019 at 4:45 pm.
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