1965 Schaub Lorenz 5001 Music Centre - Page 2 - UK Vintage Radio Repair and Restoration Discussion Forum

Jimmyhaflinger · 1st Sep 2015, 10:36 pm

the transparent leader is only at the beginning of the tape, the end is detected only by the cam gear contacts

please DO NOT attempt to adjust the cam gear unless you know damn well what you're doing... i did it and had to get the service manual in German and translate it, and even then it was a real pain to get it right again

af024 · 2nd Sep 2015, 1:19 pm

Hello David and Jimmyhaflinger,

Thank you for further clarification.

I don't mind saying that I'm really really apprehensive about adjusting the cam gear, but hopefully if I can see how it works, I should, with extreme care be able to adjust it to bring the leader into being upon a re-wind. My fear is that the rewind stop setting might affect the forward stop setting.

Perhaps I can somehow reduce the torque of rewind motor (by suitable insertion of a high wattage resistor or some such), just in case I get things really wrong. It might offer a bit of protection?

Hopefully there's a lot of leader in there ....

Thank you again,

Andy

Jimmyhaflinger · 2nd Sep 2015, 2:38 pm

there ain't any kind of leader at the end of the tape, the magnetic tape is just glued onto the hub with a few extra turns, be careful as it won't be easy to glue it back correctly if it gets torn off

if you need to adjust the timing, it's safer to loosen the cam gear contact bracket and adjust their position by a fraction of a millimetre so that the cam gear opens them slightly before or later, instead of messing with the cam gear itself

I would let the rewind motor alone, there's a carefully selected series NTC to limit its torque at startup to avoid damaging the tape, any alteration to this circuit may lead to unpredictable results, and with the heavy metal reels there would be enough inertia to tear the tape off the hub even at a reduced rewind speed

af024 · 5th Sep 2015, 1:57 pm

Thank you for further advice.

When I'm brave enough (and I have dug out some more bench space!) I'll have a bit of a go.

Does anyone know how much leader exposed upon rewind would be normal for these? Actually, that's probably difficult to judge on the basis that the circuit involving the LDR might well wind it back onto the take-up before the length can be judged! Mmmm

Regards,

Andy

Jimmyhaflinger · 6th Sep 2015, 12:06 am

it all depends on how well your machine's brakes are working

mine takes about 10 seconds to "play" the section of clear leader before the tape begins,

if the LDR fails the clear leader won't stop the rewinding and the machine will rewind until the timing gear stops it, if even the timing gear fails, then the clear leader will get torn off the hub, something you don't really want to happen

Phil G4SPZ · 6th Sep 2015, 11:31 pm

What an interesting yet fiendish machine! Well done on getting yours working, Dave. What's the audio like on tape recordings - is it full FM quality?

af024 · 7th Sep 2015, 7:57 pm

Thank you for your further info/advice.

So does the LDR (and associated logic) also initiate a stop end the end of re-wind sequence then (i.e. a stop once the leader appears), or does it cause a track increment when the thing goes back into play at the junction of the leader and tape?

It's just that mine doesn't actually reach the leader upon a re-wind.

Funny too, but the LDR on the circuit I have states LDR04 and not LDR05 (which is quoted for the record level circuit). Perhaps LDR04 is a misprint and it really is an LDR05?

Fiendish for sure Phil! Oh, and from what I've heard off the tap so far, it sounds remarkably good.

Radio_Dave · 7th Sep 2015, 8:37 pm

Quote:

Originally Posted by Phil G4SPZ

What an interesting yet fiendish machine! Well done on getting yours working, Dave. What's the audio like on tape recordings - is it full FM quality?

Hi Phil, The recordings on this one are awful, fading in and out, AM recordings, mainly badly edited Top 20 type stuff. Even so I'd never record over anything. I have used one unused track to record some music from my ipod and does sound very good.

Quote:

Originally Posted by af024

So does the LDR (and associated logic) also initiate a stop end the end of re-wind sequence then (i.e. a stop once the leader appears), or does it cause a track increment when the thing goes back into play at the junction of the leader and tape?

The LDR should stop the tape from rewinding. The switch gear is there for backup. It sound like your switch gear needs adjusting, which is all covered in the service manual available in post #11

David

af024 · 7th Sep 2015, 9:02 pm

Thank you David,

Switch gear is it then.

Regards,

Andy

Jimmyhaflinger · 8th Sep 2015, 11:22 pm

Quote:

Originally Posted by af024

So does the LDR (and associated logic) also initiate a stop end the end of re-wind sequence then (i.e. a stop once the leader appears), or does it cause a track increment when the thing goes back into play at the junction of the leader and tape?

The LDR also stops the mech at the beginning of the tape when the machine is in STOP mode

Jimmyhaflinger · 8th Sep 2015, 11:26 pm

Quote:

Originally Posted by Radio_Dave

Hi Phil, The recordings on this one are awful, fading in and out, AM recordings, mainly badly edited Top 20 type stuff. Even so I'd never record over anything. I have used one unused track to record some music from my ipod and does sound very good.

just like mine, i love this kind of low-fi pop music stuff though...

BTW mine is also full of misplaced "stop tones", i need to find a way to disable the pilot tone circuit to be able to enjoy the recordings without having to keep a finger on the pause button to keep it from stopping and rewinding a few minutes into a track or even at the beginning

1st Sep 2015, 10:36 pm	#21
Jimmyhaflinger Heptode Join Date: Feb 2007 Location: La Spezia, Italy Posts: 834	Re: 1965 Schaub Lorenz 5001 Music Centre the transparent leader is only at the beginning of the tape, the end is detected only by the cam gear contacts please DO NOT attempt to adjust the cam gear unless you know damn well what you're doing... i did it and had to get the service manual in German and translate it, and even then it was a real pain to get it right again

2nd Sep 2015, 1:19 pm	#22
af024 Octode Join Date: Jan 2003 Location: Ashby-de-la-Zouch (it's not by the sea) Posts: 1,255	Re: 1965 Schaub Lorenz 5001 Music Centre Hello David and Jimmyhaflinger, Thank you for further clarification. I don't mind saying that I'm really really apprehensive about adjusting the cam gear, but hopefully if I can see how it works, I should, with extreme care be able to adjust it to bring the leader into being upon a re-wind. My fear is that the rewind stop setting might affect the forward stop setting. Perhaps I can somehow reduce the torque of rewind motor (by suitable insertion of a high wattage resistor or some such), just in case I get things really wrong. It might offer a bit of protection? Hopefully there's a lot of leader in there .... Thank you again, Andy __________________ Now where on earth did I remove that from?

2nd Sep 2015, 2:38 pm	#23
Jimmyhaflinger Heptode Join Date: Feb 2007 Location: La Spezia, Italy Posts: 834	Re: 1965 Schaub Lorenz 5001 Music Centre there ain't any kind of leader at the end of the tape, the magnetic tape is just glued onto the hub with a few extra turns, be careful as it won't be easy to glue it back correctly if it gets torn off if you need to adjust the timing, it's safer to loosen the cam gear contact bracket and adjust their position by a fraction of a millimetre so that the cam gear opens them slightly before or later, instead of messing with the cam gear itself I would let the rewind motor alone, there's a carefully selected series NTC to limit its torque at startup to avoid damaging the tape, any alteration to this circuit may lead to unpredictable results, and with the heavy metal reels there would be enough inertia to tear the tape off the hub even at a reduced rewind speed

5th Sep 2015, 1:57 pm	#24
af024 Octode Join Date: Jan 2003 Location: Ashby-de-la-Zouch (it's not by the sea) Posts: 1,255	Re: 1965 Schaub Lorenz 5001 Music Centre Thank you for further advice. When I'm brave enough (and I have dug out some more bench space!) I'll have a bit of a go. Does anyone know how much leader exposed upon rewind would be normal for these? Actually, that's probably difficult to judge on the basis that the circuit involving the LDR might well wind it back onto the take-up before the length can be judged! Mmmm Regards, Andy __________________ Now where on earth did I remove that from?

6th Sep 2015, 12:06 am	#25
Jimmyhaflinger Heptode Join Date: Feb 2007 Location: La Spezia, Italy Posts: 834	Re: 1965 Schaub Lorenz 5001 Music Centre it all depends on how well your machine's brakes are working mine takes about 10 seconds to "play" the section of clear leader before the tape begins, if the LDR fails the clear leader won't stop the rewinding and the machine will rewind until the timing gear stops it, if even the timing gear fails, then the clear leader will get torn off the hub, something you don't really want to happen

6th Sep 2015, 11:31 pm	#26
Phil G4SPZ Dekatron Join Date: Apr 2005 Location: Bewdley, Worcestershire, UK. Posts: 4,748	Re: 1965 Schaub Lorenz 5001 Music Centre What an interesting yet fiendish machine! Well done on getting yours working, Dave. What's the audio like on tape recordings - is it full FM quality? __________________ Phil Optimist [n]: One who is not in possession of the full facts

7th Sep 2015, 7:57 pm	#27
af024 Octode Join Date: Jan 2003 Location: Ashby-de-la-Zouch (it's not by the sea) Posts: 1,255	Re: 1965 Schaub Lorenz 5001 Music Centre Thank you for your further info/advice. So does the LDR (and associated logic) also initiate a stop end the end of re-wind sequence then (i.e. a stop once the leader appears), or does it cause a track increment when the thing goes back into play at the junction of the leader and tape? It's just that mine doesn't actually reach the leader upon a re-wind. Funny too, but the LDR on the circuit I have states LDR04 and not LDR05 (which is quoted for the record level circuit). Perhaps LDR04 is a misprint and it really is an LDR05? Fiendish for sure Phil! Oh, and from what I've heard off the tap so far, it sounds remarkably good. __________________ Now where on earth did I remove that from?

7th Sep 2015, 9:02 pm	#29
af024 Octode Join Date: Jan 2003 Location: Ashby-de-la-Zouch (it's not by the sea) Posts: 1,255	Re: 1965 Schaub Lorenz 5001 Music Centre Thank you David, Switch gear is it then. Regards, Andy __________________ Now where on earth did I remove that from?