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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 17th Jul 2021, 7:52 am   #1
DMcMahon
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Default National Panasonic RS-260USD Cassette Deck Checkout

An initial checkout of this 1972 stereo cassette deck that I recently purchased.

An attractive compact basic player/recorder in good condition overall.

Mechanically all basically works, tape transport control is good. Cassette eject operation a little haphazard.

Playback only works on the left channel, both to headphones and phono line outs, the right channel is silent.

There are 2 rotary controls on the top panel identified as Volume but have no affect on playback volume. If I have correctly identified them on the schematic they appear to be recording level adjustments only.

Recording only works on the right channel, the right "Volume control" having adjustment of the record level as shown on the VU meter. On playback the recording plays back with distortion but this conflicts with Playback on the right channel not originally working ??

Need to go inside and investigate.

David
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Old 17th Jul 2021, 8:17 am   #2
Ted Kendall
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Default Re: National Panasonic RS-260USD Cassette Deck Checkout

Clean the record/play switch before anything else, I would...
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Old 17th Jul 2021, 9:59 am   #3
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Default Re: National Panasonic RS-260USD Cassette Deck Checkout

Spot on Ted.
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Old 17th Jul 2021, 10:24 am   #4
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Default Re: National Panasonic RS-260USD Cassette Deck Checkout

Thank you Ted and Paul, that is on the planned agenda.

David
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Old 17th Jul 2021, 2:34 pm   #5
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Default Re: National Panasonic RS-260USD Cassette Deck Checkout

Have disconnected the obvious but the chassis is not keen to come out of the case, something is holding it quite solid around the cassette area.

Maybe could access the Play/Record switch for cleaning as it is but want to inspect/clean the top side, heads etc.

David
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Old 17th Jul 2021, 8:00 pm   #6
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Default Re: National Panasonic RS-260USD Cassette Deck Checkout

Removed the chassis from the case (tight fit) after locating the cross headed screw in photo 1 that was the culprit that was the final screw that was holding the chassis.

Now need to gently lift up the PCB to see/gain access to the Play/Record switch for cleaning, this looks like it might be tight due to attached cables.

David
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Old 19th Jul 2021, 10:30 pm   #7
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Default Re: National Panasonic RS-260USD Cassette Deck Checkout

After lifting the PCB cleaned the Play/Record slide switch, also cleaned the volume controls (actually record level controls).

Did some general cleaning and lubrication.

Cleaned up tarnished phono socket connectors that were making it difficult to plug in the phono cables.

Now all re-assembled and everything working very well.

David
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Old 19th Jul 2021, 10:42 pm   #8
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Default Re: National Panasonic RS-260USD Cassette Deck Checkout

While cleaning pulled out a lump of what I thought was fluff from the end of the spring for the cassette eject mechanism, then saw that it was a length of orange foam as per photo.

In the photo there is similar lengths of foam in other springs, what is the function of the foam, noise dampening possibly ?

David
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Old 19th Jul 2021, 10:44 pm   #9
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Default Re: National Panasonic RS-260USD Cassette Deck Checkout

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Cleaned up tarnished phono socket connectors that were making it difficult to plug in the phono cables.

David
Can anybody recommend a good non messy clear electrically conductive grease ?

David
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Old 20th Jul 2021, 8:23 am   #10
Ted Kendall
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Default Re: National Panasonic RS-260USD Cassette Deck Checkout

Deoxit is good for phono socket oxidation. Use a squirt on a Q-tip, and the metal is soon revealed.
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Old 20th Jul 2021, 8:32 am   #11
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Default Re: National Panasonic RS-260USD Cassette Deck Checkout

Thank you Ted. I tried Deoxite D5 and it did not do a very good job, so had to use crocus paper to get them looking clean (they were heavily tarnished) and be able to get the phono cables to plug in easier.

David

Last edited by DMcMahon; 20th Jul 2021 at 8:54 am. Reason: Typo
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Old 25th Jul 2021, 9:25 am   #12
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Default Re: National Panasonic RS-260USD Cassette Deck Checkout

The foam strips are indeed there to damp any 'tinging' sounds generated by the springs. ISTR some decks sounding like a campanology class.
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Old 8th Oct 2021, 8:39 pm   #13
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Default Re: National Panasonic RS-260USD Cassette Deck Checkout

Planning to sell it, so tonight have been checking it out again and and now find that the left channel is playing up on playback of new recordings (low volume and distorted sound). Playback of known good recordings is still good on both channels and playback of new recording is also bad on the left channel when played back on other recorders.

So looks like the left channel for some reason is not good when recording, have not yet checked to see if erase is working well on the left channel.

David
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Old 8th Oct 2021, 11:49 pm   #14
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Default Re: National Panasonic RS-260USD Cassette Deck Checkout

Removed the chassis from its case with intention of cleaning the heads and Play/Record switch again and do any required monitoring, but now when chassis is powered up both VU meters go hard over and when Play is pressed get very loud hum on both channels plus the motor is now not working

So something nasty is occurring.

David
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Old 8th Oct 2021, 11:59 pm   #15
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Default Re: National Panasonic RS-260USD Cassette Deck Checkout

Dirty or displaced rec/rep slide switch, I'd say, thogh the motor fault could be something else. This uses a continuously running AC motor, doesn't it? .

Last edited by Ted Kendall; 9th Oct 2021 at 12:07 am.
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Old 9th Oct 2021, 9:26 am   #16
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Default Re: National Panasonic RS-260USD Cassette Deck Checkout

The RS-260US schematic shows a switch in series with the motor called Motor switch (closed position identified as Play), so from that I do not think the motor is continuously running, it is a DC motor.

There are a few minor differences in the power circuitry on the RS-260US schematic (could not easily find anything else) compared to my RS-260USD, the schematic shows a single pole mains switch and a mains voltage selection switch whereas my RS-260USD has a 2 pole mains switch and no mains voltage selection switch.

The schematic also only shows one fuse (value not identified) fusing one side of the mains supply. My RS-260USD has two 325mA slow blow 20mm glass fuses, one of which has blown.

So need to trace where the blown fuse connects to and checkout if a fault still exists on it before renewing the fuse.

David
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Old 9th Oct 2021, 10:59 am   #17
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Default Re: National Panasonic RS-260USD Cassette Deck Checkout

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The schematic also only shows one fuse (value not identified) fusing one side of the mains supply. My RS-260USD has two 325mA slow blow 20mm glass fuses, one of which has blown.

David
325mA should have read 315mA

David
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Old 9th Oct 2021, 2:43 pm   #18
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Default Re: National Panasonic RS-260USD Cassette Deck Checkout

Checked out the power circuitry. The double pole mains switch connects direct to the mains transformer primary winding, i.e. not fused, so different from the RS-260US schematic.

The two 315mA fuses are on the 2 outputs from the mains transformer secondary winding, these 2 fuses then each feed a rectifier diode and smoothing capacitor, one rectified output feeds the electronics via a regulating transistor and the other rectified output feeds the DC motor via the motor switch (switch is closed when Play, FFD or RWD is selected.

The fuse for the motor also feeds the two lamps for the VU meters.

The fuse that had blown was the motor fuse.

After checking all the associated circuity with no faults found, replaced the motor fuse and powered up. The VU meters lamps illuminated normally but after around 10 secs the motor fuse blew again, had not attempted to drive the motor.

Double checked everything and again nothing found wrong. Have disconnected the VU meter lamps and now the fuse is not blowing, more tests required.

Why this fuse blowing problem suddenly occurred after first removing the chassis to investigate the record problem on the right channel currently is a mystery.

David
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Old 9th Oct 2021, 4:50 pm   #19
Ted Kendall
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Default Re: National Panasonic RS-260USD Cassette Deck Checkout

Maybe you have trapped one of the lamp wires?
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Old 9th Oct 2021, 8:04 pm   #20
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Default Re: National Panasonic RS-260USD Cassette Deck Checkout

I wondered the same but nothing obvious found, I removed the lamp assembly to be sure that the lamp wires were not trapped/damaged.

Have been doing loads of voltage and current measurements but results only have confused me.

For no obvious reason the fuse is not currently blowing, but there is a problem with the lamps. With only 1 lamp wired all is good and motor runs OK, they both do the same individually.

With both lamps wired they go very dim very quickly after switch on, the current through them stays the the same but the voltage across them drops right off, not yet able to work out why.

David
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