Tandberg Series 6 restoration help please - UK Vintage Radio Repair and Restoration Discussion Forum

jascha · 18th Sep 2020, 7:26 am

Hi everyone,
I would like some help please with a restoration on my newly acquired Tandberg Series 6 (2 Track).

Firstly can I ask if a service manual of the model 62 will be sufficient for me to use as I can’t seem to find a link to download the right version for my machine, unless someone can help me out with a SM pdf copy please.

The difficulty seems to be on how to carefully get to the underside of the playback and record pcbs taking into account that not only there are wires soldered to the board but also an eq strip which is tied across the 2 boards.

I would also need to get to the filter caps and selenium rectifiers which seems almost impossible to reach and if anyone has some detailed instructions on how to get to them for replacement/ reforming I would be most grateful for any help please. I like to replace selenium with modern silicons for peace of mind and safety too.

How much does a series 6 2 Track differ from a later model 62 please, apart from not having the free position on the former?

Many thanks

Ted Kendall · 18th Sep 2020, 9:25 am

The 62 and the Series 6 two track are the same machine. There were only minor changes in the Series 6 until the introduction of the 6X in 1968, which used cross-field bias. The "free" position is simply a mechanical aid to threading, which disengages both reel clutches. Hellyer wrote an informative Tape Recorder Service article around 1967-8, available on World Radio History (Studio Sound).

jascha · 18th Sep 2020, 11:01 am

Many thanks Ted. I shall try and find the article by Hellyer as that would be very useful.

Kind regards

Ted Kendall · 18th Sep 2020, 6:12 pm

https://worldradiohistory.com/Archiv...nd-1968-11.pdf

Articles in succeeding months deal with other models, touching on matters relevant to the 6.

jascha · 18th Sep 2020, 6:21 pm

I look forward to reading the article. Thanks for that. Since my last post earlier my Tandberg is having its filter caps reformed section by section and the wooden cabinet restored with 2 nice coats of linseed oil after cleaning it up from what it needed to be cleaned of.

Looking forward to get it all done and ready

jascha · 18th Sep 2020, 9:17 pm

Any ideas for replacements of the pads on the reel tables please? They seem to have partly perished and from what I read some people use cork pads. I measured the gap to measure the thickness and the take up reel pad seems to measure around 5mm in thickness and the supply reel pad around 5.8mm.
Should they be the same size in diameter and in thickness please?

Thanks

barretter · 19th Sep 2020, 12:28 am

Quote:

Originally Posted by jascha

Hi everyone,
I would like some help please with a restoration on my newly acquired Tandberg Series 6 (2 Track).

Firstly can I ask if a service manual of the model 62 will be sufficient for me to use as I can’t seem to find a link to download the right version for my machine, unless someone can help me out with a SM pdf copy please.

The difficulty seems to be on how to carefully get to the underside of the playback and record pcbs taking into account that not only there are wires soldered to the board but also an eq strip which is tied across the 2 boards.

You can find a service manual for the Series 6 at www.audioservicemanuals.com
Just Google Tandberg 6 service manual and scroll down until you find this site.
I have replaced all the Rifa caps on the replay board in mine and as I recall (it was a few years ago) you just carefully remove the spring holding in place the lever which moves the equalisation strip and it can be lifted along with the circuit board when you have removed the four screws in the corners but not completely inverted unless you
desolder all the wires you mention, so it's a bit difficult to get at the capacitors. You also have to be careful not to damage the PC tracks.

ricard · 19th Sep 2020, 5:18 am

Quote:

Originally Posted by jascha

Any ideas for replacements of the pads on the reel tables please? They seem to have partly perished and from what I read some people use cork pads.

That's odd, as far as I know all Tandbergs of this vintage use felt pads, or rather rings.

The two issues I've had with the felt rings is that a) the glue they're attached with dries out and they come loose (easy enough to remedy once the tops of the reel tables have been removed), and b) they loose their friction so winding and braking is not as positive as it should be.

On the subject of Tandberg service manuals, one excellent collection can be found at http://sportsbil.com/tandberg/ .

I can second that replacing the Rifa caps on this model is paramount, for some reason the leaky Rifas cause all sorts of problems in the amplifiers, more than I've experienced in other machines.

jascha · 19th Sep 2020, 7:04 am

Thanks to your replies guys. I have to correct myself in that the pads have actually not perished but have been slightly attacked by woodworm and left some holes in them! When I took the tables off to have a closer look I realised that they can still be used and there were no signs of the bugs around! They did attack the wooden casing but it’s been restored nicely and looks great. I did not know that the take up spool carrier pad has a smaller diameter than the other table so it looked at first that they had been eaten up. They can still be used I think so I shall see when I get it all together again!

The rifa caps will be replaced after I finish reforming the filter caps section by section and which hopefully reform well so I don’t have to replace them as it’s rather awkward to work underneath considering the restrictions caused with most of the cables still soldered onto the boards. What I will replace however are the selenium rectifiers whilst I’m at it and go for silicon ones ( I will drop the voltage on the heaters to match the original voltage).

The service manual for the model 6 that I have found has very dotted images unfortunately when enlarging them but still better to have a reference than nothing.

Regards

jascha · 19th Sep 2020, 8:58 am

Here are images of the reel tables

jascha · 22nd Sep 2020, 7:18 am

Hi everyone,
Yesterday I got to the point of having replaced all the rifa caps and reformed caps and replaced rectifiers with modern silicon ones and it’s all going as planned. I noticed however that I had a couple of ECC81 valves and possibly what seemed to be an ECC85 (print rubbed off and type of valve just written with a sharpie on the glass)!

I have replaced the suspicious valves with what the Series 6 manual recommends which mentions 6 ECC83 and 3 ECC82! Looking at the model 62 schematic however there is mention of 2 ECC81 that replaced 2 of the ECC83!
I’m rather confused as what valves I should be using on my machine and need some help please.

I have done a test run just to check for shortages and that all the painstaking work I have done is all good to go and thumbs up so far!

Should I be using ECC81 as well ? It’s the possibly ECC85 valve that caused suspicion that there could have been some tampering by a possible cowboy before!
Belts and pinch roller will be the next target!
Many thanks.

barretter · 22nd Sep 2020, 10:57 am

The ECC85 would definitely be wrong - are you sure it's not just a badly written 3? If it's a valve made by one of Philips' network of manufacturers (which included Mullard) it would have a code written in indelible ink somewhere round the bottom half of the tube which indicates the valve type and where it was made and when. You have to look it up on a list which is available on the web.
Tandberg did change a couple of the valves on the record board from ECC83 to ECC81. This also involved changing some other components and you can find the details in the Hellyer review cited by Ted Kendall. That should enable you to determine if the change from 83 to 81 was made on your machine.

jascha · 22nd Sep 2020, 12:22 pm

Thanks for your reply. The writing on the dubious tube seems clearly marked with a 5 at the end and I did look floor the small printed letters and numbers but did not see any and will have a closer look again. I shall read the review by Hellyer and from the components I saw on my boards I get the impression that the ECC81 should not be there!
It’s a curious one!

jascha · 22nd Sep 2020, 2:54 pm

What about pinch rollers for these machines? Any suggestions please where best to get one?
Thanks

jascha · 23rd Sep 2020, 6:11 pm

I would like to clean and re-lubricate the bearings of the flywheel. How do I dismantle what is necessary to take the flywheel our safely for cleaning it please?

Thanks

barretter · 23rd Sep 2020, 7:48 pm

Quote:

Originally Posted by jascha

What about pinch rollers for these machines? Any suggestions please where best to get one?
Thanks

I bought one on eBay from Germany about five years ago and it was £36 plus postage. Currently there are a couple on eBay from Germany at £55 each plus postage. Is your pinch roller in really bad condition? Have you tried refurbishing it? Mine looked like a rubber cogwheel so it had to be replaced.
I have no idea about the flywheel.

jascha · 23rd Sep 2020, 8:47 pm

Thanks for your response. The pinch roller I have is not yet a cog wheel but it has very weak grip and it’s got cracks. I have ordered one from Italy (www.sofh.it) for €47 including postage to UK. Then I need to address also the idler wheel and refurbish it as it’s a bit noisy.

ricard · 25th Sep 2020, 11:40 pm

Lasse Hovde (lasse72@frisurf.no) in Norway does a good job of refurbishing original pinch rollers (he also sells friction pads for reel table clutches for later Tandberg models).

Sometimes the outermost, hardened layer of rubber on the idler can be sanded away to make it quieter.

jascha · 25th Sep 2020, 11:44 pm

Thanks Ricard
I took of the idler wheel yesterday and gently put it on my micro lathe and applied a bit of light sandpaper while it spinned around just to take off the hard edge. It helped however it's still kind of noisy. I wonder if the tracking needs adjusting and is causing the extra noise. I mean to say that the idler wheel might be slightly off axis against the flywheel and need to bend slightly the idler wheel arm. It's a thought.

ricard · 26th Sep 2020, 7:52 am

It's certainly worth trying, but in my experience it's the rubber on the flywheel that's the culprit, and needs replacing if it's not just the edge that is hard. I think the problem is exacerbated by the fact that on some models at least, the motor pulley has ridges in it to help increase the friction, which places even higher requirements on the resilience of the idler rubber. Not a problem when the machine was new, but making life difficult 50+ years down the line.

18th Sep 2020, 7:26 am	#1
jascha Hexode Join Date: Nov 2005 Location: Kent, UK. Posts: 332	Tandberg Series 6 restoration help please Hi everyone, I would like some help please with a restoration on my newly acquired Tandberg Series 6 (2 Track). Firstly can I ask if a service manual of the model 62 will be sufficient for me to use as I can’t seem to find a link to download the right version for my machine, unless someone can help me out with a SM pdf copy please. The difficulty seems to be on how to carefully get to the underside of the playback and record pcbs taking into account that not only there are wires soldered to the board but also an eq strip which is tied across the 2 boards. I would also need to get to the filter caps and selenium rectifiers which seems almost impossible to reach and if anyone has some detailed instructions on how to get to them for replacement/ reforming I would be most grateful for any help please. I like to replace selenium with modern silicons for peace of mind and safety too. How much does a series 6 2 Track differ from a later model 62 please, apart from not having the free position on the former? Many thanks

18th Sep 2020, 9:25 am	#2
Ted Kendall Dekatron Join Date: Jul 2008 Location: Kington, Herefordshire, UK. Posts: 3,670	Re: Tandberg Series 6 restoration help please The 62 and the Series 6 two track are the same machine. There were only minor changes in the Series 6 until the introduction of the 6X in 1968, which used cross-field bias. The "free" position is simply a mechanical aid to threading, which disengages both reel clutches. Hellyer wrote an informative Tape Recorder Service article around 1967-8, available on World Radio History (Studio Sound).

18th Sep 2020, 11:01 am	#3
jascha Hexode Join Date: Nov 2005 Location: Kent, UK. Posts: 332	Re: Tandberg Series 6 restoration help please Many thanks Ted. I shall try and find the article by Hellyer as that would be very useful. Kind regards

18th Sep 2020, 6:12 pm	#4
Ted Kendall Dekatron Join Date: Jul 2008 Location: Kington, Herefordshire, UK. Posts: 3,670	Re: Tandberg Series 6 restoration help please https://worldradiohistory.com/Archiv...nd-1968-11.pdf Articles in succeeding months deal with other models, touching on matters relevant to the 6.

18th Sep 2020, 6:21 pm	#5
jascha Hexode Join Date: Nov 2005 Location: Kent, UK. Posts: 332	Re: Tandberg Series 6 restoration help please I look forward to reading the article. Thanks for that. Since my last post earlier my Tandberg is having its filter caps reformed section by section and the wooden cabinet restored with 2 nice coats of linseed oil after cleaning it up from what it needed to be cleaned of. Looking forward to get it all done and ready Attached Thumbnails

18th Sep 2020, 9:17 pm	#6
jascha Hexode Join Date: Nov 2005 Location: Kent, UK. Posts: 332	Re: Tandberg Series 6 restoration help please Any ideas for replacements of the pads on the reel tables please? They seem to have partly perished and from what I read some people use cork pads. I measured the gap to measure the thickness and the take up reel pad seems to measure around 5mm in thickness and the supply reel pad around 5.8mm. Should they be the same size in diameter and in thickness please? Thanks

19th Sep 2020, 7:04 am	#9
jascha Hexode Join Date: Nov 2005 Location: Kent, UK. Posts: 332	Re: Tandberg Series 6 restoration help please Thanks to your replies guys. I have to correct myself in that the pads have actually not perished but have been slightly attacked by woodworm and left some holes in them! When I took the tables off to have a closer look I realised that they can still be used and there were no signs of the bugs around! They did attack the wooden casing but it’s been restored nicely and looks great. I did not know that the take up spool carrier pad has a smaller diameter than the other table so it looked at first that they had been eaten up. They can still be used I think so I shall see when I get it all together again! The rifa caps will be replaced after I finish reforming the filter caps section by section and which hopefully reform well so I don’t have to replace them as it’s rather awkward to work underneath considering the restrictions caused with most of the cables still soldered onto the boards. What I will replace however are the selenium rectifiers whilst I’m at it and go for silicon ones ( I will drop the voltage on the heaters to match the original voltage). The service manual for the model 6 that I have found has very dotted images unfortunately when enlarging them but still better to have a reference than nothing. Regards

19th Sep 2020, 8:58 am	#10
jascha Hexode Join Date: Nov 2005 Location: Kent, UK. Posts: 332	Re: Tandberg Series 6 restoration help please Here are images of the reel tables Attached Thumbnails

22nd Sep 2020, 7:18 am	#11
jascha Hexode Join Date: Nov 2005 Location: Kent, UK. Posts: 332	Re: Tandberg Series 6 restoration help please Hi everyone, Yesterday I got to the point of having replaced all the rifa caps and reformed caps and replaced rectifiers with modern silicon ones and it’s all going as planned. I noticed however that I had a couple of ECC81 valves and possibly what seemed to be an ECC85 (print rubbed off and type of valve just written with a sharpie on the glass)! I have replaced the suspicious valves with what the Series 6 manual recommends which mentions 6 ECC83 and 3 ECC82! Looking at the model 62 schematic however there is mention of 2 ECC81 that replaced 2 of the ECC83! I’m rather confused as what valves I should be using on my machine and need some help please. I have done a test run just to check for shortages and that all the painstaking work I have done is all good to go and thumbs up so far! Should I be using ECC81 as well ? It’s the possibly ECC85 valve that caused suspicion that there could have been some tampering by a possible cowboy before! Belts and pinch roller will be the next target! Many thanks.

22nd Sep 2020, 10:57 am	#12
barretter Heptode Join Date: Jan 2006 Location: Todmorden, West Yorkshire, UK. Posts: 870	Re: Tandberg Series 6 restoration help please The ECC85 would definitely be wrong - are you sure it's not just a badly written 3? If it's a valve made by one of Philips' network of manufacturers (which included Mullard) it would have a code written in indelible ink somewhere round the bottom half of the tube which indicates the valve type and where it was made and when. You have to look it up on a list which is available on the web. Tandberg did change a couple of the valves on the record board from ECC83 to ECC81. This also involved changing some other components and you can find the details in the Hellyer review cited by Ted Kendall. That should enable you to determine if the change from 83 to 81 was made on your machine. Attached Thumbnails

22nd Sep 2020, 12:22 pm	#13
jascha Hexode Join Date: Nov 2005 Location: Kent, UK. Posts: 332	Re: Tandberg Series 6 restoration help please Thanks for your reply. The writing on the dubious tube seems clearly marked with a 5 at the end and I did look floor the small printed letters and numbers but did not see any and will have a closer look again. I shall read the review by Hellyer and from the components I saw on my boards I get the impression that the ECC81 should not be there! It’s a curious one!

22nd Sep 2020, 2:54 pm	#14
jascha Hexode Join Date: Nov 2005 Location: Kent, UK. Posts: 332	Re: Tandberg Series 6 restoration help please What about pinch rollers for these machines? Any suggestions please where best to get one? Thanks

23rd Sep 2020, 6:11 pm	#15
jascha Hexode Join Date: Nov 2005 Location: Kent, UK. Posts: 332	Re: Tandberg Series 6 restoration help please I would like to clean and re-lubricate the bearings of the flywheel. How do I dismantle what is necessary to take the flywheel our safely for cleaning it please? Thanks

23rd Sep 2020, 8:47 pm	#17
jascha Hexode Join Date: Nov 2005 Location: Kent, UK. Posts: 332	Re: Tandberg Series 6 restoration help please Thanks for your response. The pinch roller I have is not yet a cog wheel but it has very weak grip and it’s got cracks. I have ordered one from Italy (www.sofh.it) for €47 including postage to UK. Then I need to address also the idler wheel and refurbish it as it’s a bit noisy.

25th Sep 2020, 11:40 pm	#18
ricard Octode Join Date: Mar 2006 Location: Lund, Sweden Posts: 1,632	Re: Tandberg Series 6 restoration help please Lasse Hovde (lasse72@frisurf.no) in Norway does a good job of refurbishing original pinch rollers (he also sells friction pads for reel table clutches for later Tandberg models). Sometimes the outermost, hardened layer of rubber on the idler can be sanded away to make it quieter.

25th Sep 2020, 11:44 pm	#19
jascha Hexode Join Date: Nov 2005 Location: Kent, UK. Posts: 332	Re: Tandberg Series 6 restoration help please Thanks Ricard I took of the idler wheel yesterday and gently put it on my micro lathe and applied a bit of light sandpaper while it spinned around just to take off the hard edge. It helped however it's still kind of noisy. I wonder if the tracking needs adjusting and is causing the extra noise. I mean to say that the idler wheel might be slightly off axis against the flywheel and need to bend slightly the idler wheel arm. It's a thought.

26th Sep 2020, 7:52 am	#20
ricard Octode Join Date: Mar 2006 Location: Lund, Sweden Posts: 1,632	Re: Tandberg Series 6 restoration help please It's certainly worth trying, but in my experience it's the rubber on the flywheel that's the culprit, and needs replacing if it's not just the edge that is hard. I think the problem is exacerbated by the fact that on some models at least, the motor pulley has ridges in it to help increase the friction, which places even higher requirements on the resilience of the idler rubber. Not a problem when the machine was new, but making life difficult 50+ years down the line.