Panasonic K Series

[welbeck5]

Hello all,

Does anyone have any info on common faults for the panny K series decks.
I'm trying to fix one, I've learnt how to time it and had to use other parts from other donor machines like the plastic slider gear. I've also fixed the notorious motor coupler by glueing it and load and eject now work fine. I've had the pinch roller off and cleaned that, had the clutch assembly out and checked it. I also replaced the take up reel brake since this part was broken when I got the machine.


The issue I'm having is that on playback the tape rides up in the area of the audio head and I have to quickly eject the tape since it starts getting chewed. Trying to make observations is very difficult on the machine since the light sensors are sensitive and as soon as I lift the lid the machine stops.
One thing I have noticed and they could be linked, is that sometimes the p5 arm moves ahead of the tape guide and doesn't lace the tape properly - when this happens the tape plays but it's not in the right position i.e. not going through the pinch roller etc...
I've had the p5 out and cleaned and greased it to no avail and it's post is where it should be, in the plastic slide gear.

I've got a working k series machine and I have to say that for me the picture and sound is great compared to the g decks, so I thought I'd learn a bit about them but this problem has me stumped.

Hopefully it's a common fault from back in the day that someone remembers.

While I wait for any responses I'm going to clean the tape path again and give it another try and I might swap out the p5 arm for another one.


Cheers Brian

[gallowfields]

has the pinch roller got a glassy finish ? as that will make the tape ride up the ace head . if so and you havent a replacement try removing the glassy finish by use of fine emery paper .
brian

[welbeck5]

Originally Posted by gallowfields

has the pinch roller got a glassy finish ? as that will make the tape ride up the ace head . if so and you havent a replacement try removing the glassy finish by use of fine emery paper .
brian

Hello Brian,
I've tried two pinch rollers. They don't look too bad.
I'll give it a go though, I have some fine emery boards.
The erractic p5 arm is doing my napper in, the machine should repeat the correct procedure since I've timed it.
I'm limited to what I can watch with the sensors on it.
I've took the deck off the board and went through the loading procedure by hand but without seeing the tape lace, it's hard to spot anything untoward.

Cheers Bri

[welbeck5]

Well the pinch roller didn't work, but it's still a good job done and I've also swapped out the take-up tension regulator arm since it seemed a bit stiff but still no joy.
One tape plays alright, (although hi-fi sound isn't being picked up another prob for later) but when you put another tape in it starts riding.

The p5 arm is still acting up, sometimes it laces the tape sometimes it's too quick (or some other partis too slow)
I'm going to swap out the p5 arm and if that doesn't work I'll have to have a look at the power supply - I was hoping not to have to do that since looking at the schematic all the caps will need to be purchased since they're completely different values to the G series.
Cheers Bri

[Michael Maurice]

The power supply will not be the problem.

Make sure every pivot and post is cleaned and free from grease, apply fresh grease where necessary.

The pinch roller is the cause of the tape riding high, you need to fit a new pinch roller, preferably an original. A copy part is available but only to the trade.

[Welsh Anorak]

I'd certainly agree with Michael. There's no point in replacing the capacitors as the machine appears to be working correctly and just needs a pinch roller.

Panasionic did have a problem with some capacitors, but this was ironed out by your machine. Unless it's seen very high usage then I'd leave well alone.

[welbeck5]

Cheers Michael and Glyn.
I do have a working K machine so I suppose, I could try the pinch roller in that and see if it fixes it.

I'm concerned about the white slider gear (WSG) since I think over time it's become warped. This is especially noticeable when the Tension arm unit is fitted. It sits under the WSG and is supposed to move along a walled section. The original WSG that was in the machine couldn't stay pressed down and the washers were popping out all over the place, so I put another WSG in which is a little better since it holds it in place but I just wonder if this constant pressing causes the rest of the WSG to not work properly. What I find is that after I retime the back, the first time I put a tape in, it works, eject then reload and then we get the problem where the p5 either moves too quickly so the tape doesn't go through the pinch roller or it goes through the pinch roller but starts riding.
I have just bought a heat gun since I may try and heat the area of the WSG where the TAU sits and try and make it more flatter so it sits in there securely.
From what I've seen a new WSG is around £30 + foreign postage so not viable.
Hope this makes sense.

[Michael Maurice]

My experience with these is that if you replace the white slider gear or main lever as Panasonic referred to it as, you also have to replace the brake arms.

Also the main lever can develop minute cracks, perhaps thats whats causing your faults.

[welbeck5]

Originally Posted by Michael Maurice

My experience with these is that if you replace the white slider gear or main lever as Panasonic referred to it as, you also have to replace the brake arms.

Also the main lever can develop minute cracks, perhaps thats whats causing your faults.

Thanks for this info.
There's an obvious crack where the p5 sits, see photo, a slither of plastic which has been bashed over the years and given way, maybe this is why it sets off early on playback since it's not pushed all the way back to it's starting position. I'll glue it and if it holds I'll give it another try.

[welbeck5]

It's fixed!! thanks for all your help

I super-glued the damaged p5 slot in the main lever (ML) shown in the photo above, stuck a slither of blu tack in the gap to the left (which is not needed and caused the problem) and layered both sides of that with a bit of super glue. Yes, a bit of a Blue Peter repair and it might not last too long, but at least I know what's causing the prob.

I seen this break in the plastic ages ago, but dismissed it and infact the original ML had the same break, so it must be common for machines of this vintage.

So if you have k mech and need to repair the problematic motor coupler check the white ML while you're there!

I still can't get hi-fi sound, so I'll continue to clean the head and hopefully it's a bit persistent dirt that will eventually come off.

Cheers Bri

[welbeck5]

Hi fi sound might be the tape I was using since I've chucked another one in and it's fine!

[Welsh Anorak]

Yes, back in the day you just ordered and changed the damaged parts for a couple of pounds - but now good old ingenuity is the order of the day!

Yet to see a washing-up liquid bottle pressed into service a la Blue Peter, but it can only be a matter of time...

[welbeck5]

Originally Posted by Welsh Anorak

Yes, back in the day you just ordered and changed the damaged parts for a couple of pounds - but now good old ingenuity is the order of the day!

Yet to see a washing-up liquid bottle pressed into service a la Blue Peter, but it can only be a matter of time...

Sadly the Blue Peter blu tac / superglue combo is not enough since the crack has reappeared. It still plays but the hi-fi sound has gone as the p5 arm is probably not exactly where it needs to be.
So I've now took the blu tack out of the slot and filled it up with superglue, surely that will be strong enough! If not any suggestions out there would be appreciated bearing in mind the gap is about 1mm.
Attached latest photo, that dark bit in the middle of the thin plastic is just a mark and nothing serious.
But least i know what the issue is!

[spamfritter]

Clean off the superglue / blue tack and use epoxy resin ? Would that work ?

[welbeck5]

Originally Posted by spamfritter

Clean off the superglue / blue tack and use epoxy resin ? Would that work ?

I've never used epoxy resin before and I've got some in my draw, so yes if this doesn't work I'll give it a go. Cheers.

[Maarten]

Epoxy would be better as superglue is not a filler (I've heard it an be used as such mixed with baking soda but would not try first on a critical repair)

[welbeck5]

The superglue is holding out so far, but epoxy is on standby.

I did make a blooper with the alignment from a few days ago.
There was a post which lives under the main lever which wasn't positioned correctly, called the tension spring arm and was positioned on a raised edge of the main lever, it should be living in a nearby lower chamber - it was probably the main culprit.
After sorting this I then had problems getting the vcr to initialise, it was coming back with a f06 error - Pointing to the load motor according to google.

So I played around with the worm gear motor and eventually got it to seat properly,
by pulling the worm gear as far up the motor spindle as possible and the
machine seems to be working now.

I tell you what though, they say g mech is difficult to time, due to the number of timing marks and parts, but I think overall the k mech is much more difficult, for starters, each time you have a problem you have to unscrew everything and take all the, now fragile, flexi cables (with the blue backs which now fall off easy) out which is a delicate job and an extreme faff. The motor worm gear has to be sat just right and the main lever is not your friend. And getting the load connection gear to engage properly with the main cam gear is agony. Other than that it's great fun.

[welbeck5]

I've now plastic welded it! Ugly looking thing now, but it works.



cheers Bri