Brenell Mk5 Restoration - UK Vintage Radio Repair and Restoration Discussion Forum

Cameron · 14th Apr 2017, 7:18 pm

A few years ago, having restored a couple of cheap reel-to-reel decks successfully, I plucked up the courage to purchase a Brenell Mk5. It was advertised on eBay as fully working, however when it arrived it wasn't and blatantly hadn't been for some years.

Life got in the way and the Brenell was shelved for later, and I've just dug it out and plugged it in to see what's going on with it.

- It powers up, the "Playback" light illuminates straight away.
- Fast-Forward and Rewind work perfectly
- There's audio coming through the speaker and the amp isn't making any unusual noises

However, Playback doesn't work. All I can hear is the reel tables spinning underneath. I'm assuming that there's rubber pads that will have worn away/hardened over the years that are stopping it from playing back? Manually spinning the tape confirms that the amp is working as sound comes out loud and clear.

More importantly, after a couple of minutes of being turned on, a strong burning smell develops, much like the smell that an iron makes when you use it. I noticed that the 'Record Level' tube doesn't light up, but one tiny yellow spark slowly lights up as the burning smell starts - is this a failed tube or something more sinister?

I'd really like to give this deck a thorough service and finally get to enjoy using it. The case is really clean, as is the deck on top.

If anyone can advise on how I should tackle these issues and perhaps point me in the direction of a service manual for it (I've had a look on Google and can't seem to find anything), that would be really appreciated.

Thanks in advance,
Cameron.

Cameron · 14th Apr 2017, 7:40 pm

On closer inspection, the Mullard EM87 tube looks to have expired inside. There's a black burn mark in the side of it. I think this is the source of the burning smell. All the capacitors look visually okay, I'm not sure how to test them otherwise though.

Boater Sam · 14th Apr 2017, 7:42 pm

Not really a good idea to just plug it in and hope, you could be doing a lot of damage.
Have a read of the "stickies" on this site about starting renovations.

To help you we need to know your level of ability, experience and what tools/test equipment you can access.

There are posts re Brenells on here, do a search in the box at the top.
Someone will find the service info, there is a website, brenelltape.co.uk.websitebuilder.prositehosting.co .uk/

Sam.

Cameron · 14th Apr 2017, 8:18 pm

Thanks for your reply Sam,

I just trusted that it was okay to use because the person who sold it me on eBay had it pictured plugged in with the lights on and said it was 100% fully working. I should have queried it at the time, but guessed maybe something got damaged in the post.

I've restored a Philips EL3515 before with new pads, new belts, demagentizing the heads etc... and then a Sony TC-377 which was a similar job. Both done with kits on eBay. I have electrical screwdrivers, a multimeter, tape head demagnetizer, soldering iron but that's about it. I can deal with most of the issues that the decks have given me, but I'm not brilliant with circuitry work.

I've already had a good search on the forum about Brenells, but can't seem to find a topic describing the problems that I'm having with mine. I've seen the website too, it's helped me date my unit to 1964-1966. But I haven't found any information about servicing on there.

Boater Sam · 14th Apr 2017, 9:17 pm

EM87 is a valve, electrofluorecent display, and they can't make a smell unless smashed. The "burn" mark could just be the getter inside the envelope, normal.
This could be a red herring. Valves are very reliable and providing they still have a vacuum don't age if unused.

Before connecting to any power, look for a resistor that has got hot, smell around any motor, transformer, wound components. Any bulging capacitors? Eyes, nose and ears find many faults.

It is possible that it was working but age has caught up with a capacitor and it has gone electrically leaky.

Establish a positive fault finding sequence, without guessing, to achieve a solution.
You need to find a circuit diagram at least, is the Brenell site any help?

Sam.

Boater Sam · 14th Apr 2017, 9:23 pm

Is this your unit? If so you can download the circuit diagram (they send it to your email) free but don't publish it anywhere please.

http://www.radiomuseum.org/r/brennel...amplifier.html

Sam.

Diabolical Artificer · 15th Apr 2017, 6:24 am

Schematics and useful info available here - http://www.schimmel.talktalk.net/tap...ne/brenell.htm

Sams right, never a good idea to wing it by plugging vintage anything straight off the main's, which is probably what the original seller did; all a lit light bulb tells you is that there is power out of the main's tfmr and the lightbulb works.

To start with a warning THERE ARE VOLTAGES PRESENT INSIDE YOUR BRENNEL THAT CAN KILL
you might be aware of this, but we don't know that, so good to let you know.

Secondly, there are various Brennel Mk5's, mono, stereo version's etc.

As Sam says there are "stickies" which are informative threads that deal with some aspects of vintage gear restoration. For instance if you use the "search this website" box at the top of the page to find threads on how to test a capacitor, you get something like this - https://cse.google.com/cse?cx=008872...ors&gsc.page=1

Before you power it up again make a lamp limiter, instruction's here - http://www.vintage-radio.com/projects/lamp-limiter.html this will help reduce any damage by limiting current to your machine and give a visual indication of it's "health"

Next you need to do a good visual inspection, test and replace any faulty capacitors, especially coupling caps. When your at that point we can go further.

Lastly, see if the motors are turning or even better see if you have 240v at the motors and that the motor run caps are ok.

Good luck, Andy.

Cameron · 15th Apr 2017, 3:00 pm

Thanks both for your replies. Mine is a slightly later Brenell Mk5 than the one that Sam posted, this is a photo of an identical model to mine: http://files.websitebuilder.prositeh.../mk5s2reel.jpg. It's mono, with the original tape heads, though it has the upgraded capstan to allow it to play back at 15ips.

I've come across the Brenell website many times, however this is the first time I've noticed the circuit diagrams. So thanks for pointing me towards them.

The motors definitely work, the FF/RW works perfectly, but you can hear the reel tables slipping on playback.

I have to admit, this is getting a little bit over my head with this now. I can cope with mechanicals but electricity isn't my friend - I've been vexed fitting electric ignition to my Rover P6 this weekend, so this kind of circuitry is beyond my capabilities for now! I'd love to learn, but I learn best watching someone else and then having a go. I can't find any videos on YouTube about restoring a Brenell.

Are there any specialist repairers near to Derby/Nottingham? That's where I've just moved to. There was a guy in Leeds where I lived before but it seems a long way to go to take a tape deck for repair.

But for now I'll take the deck apart again and visually inspect the capacitors to see if there's anything visually amiss. Thanks again.

Tractorfan · 15th Apr 2017, 9:56 pm

Hi,
The 'burn' mark is normal inside a valve and is the getter that has done its stuff and mopped up any stray molecules of gas left behind during evacuation. If you suspect that there's a short within it (unlikely), you can simply unplug it and see if the burning smell stops. Are you sure that the 'tiny yellow spark' isn't just the heater warming up? It's about half way up the valve, and right at the back. Forgive me if I'm stating the obvious.
Cheers, Pete.

Boater Sam · 15th Apr 2017, 10:12 pm

There is a section on this forum to request members who repair or mentor.
If you can't find anything obvious, post for help in this section, there are lots of members around you.

Diabolical Artificer · 16th Apr 2017, 5:28 am

Your welcome to pop over here if it helps Cameron, it's about an hours drive. I have a Brennel 5 I need to sort, happy to have a Brennel fixing day.

Drop us a PM if interested.

Andy.

Boater Sam · 16th Apr 2017, 11:59 am

Now there is an offer not to be missed Cameron, a day with the Master on the bench.
You will learn more in that day than a month asking on the forum, bet there are bacon butties too.

Diabolical Artificer · 17th Apr 2017, 5:05 am

Hardly a Master Sam, just a bit more along than Cameron. Sorry no bacon butty's either, though Molly won't mind you pinching a few of her sausages if your inclined. : )

A.

Old Dave · 6th May 2017, 7:15 am

Hi All,

Tacking onto Cameron's post because it's easier that typing it all out again.
I pulled my Dad's old Brenell Mk 5 (Series 1? with white/bone head covers) from the garage while waiting on parts for another machine.

Following Boater Sams advice (Before connecting to any power, look for a resistor that has got hot, smell around any motor, transformer, wound components. Any bulging capacitors? Eyes, nose and ears find many faults) I found the one he was looking for! It measures 770 ohms out of circuit.

I powered it up and the results are pretty much the same as Cameron's.
Replaced the counter belts. Flywheel somewhat reluctant when in Playback.

What was that about a resistor? Suspect resistor is getting hot, >60 degrees C.

Power off, take photo's & close the box until electrical issues are resolved.

Picture added. I can't read anything on the resistor and am in need of the schematics & service manual.

Help please?

Thanks,
Dave

jamesperrett · 10th May 2017, 12:08 pm

If you are talking about that grey resistor in the front of the photo then it is supposed to get fairly hot - they wouldn't have fitted quite such a large one if it they didn't expect it to heat up. As far as I can remember, it is connected to the take up motor circuit in play mode in order to reduce the current through the take up motor so it should only get hot when the deck is in play mode.

14th Apr 2017, 7:18 pm	#1
Cameron Retired Dormant Member Join Date: Oct 2010 Location: Nottingham, Nottinghamshire, UK. Posts: 56	Brenell Mk5 Restoration A few years ago, having restored a couple of cheap reel-to-reel decks successfully, I plucked up the courage to purchase a Brenell Mk5. It was advertised on eBay as fully working, however when it arrived it wasn't and blatantly hadn't been for some years. Life got in the way and the Brenell was shelved for later, and I've just dug it out and plugged it in to see what's going on with it. - It powers up, the "Playback" light illuminates straight away. - Fast-Forward and Rewind work perfectly - There's audio coming through the speaker and the amp isn't making any unusual noises However, Playback doesn't work. All I can hear is the reel tables spinning underneath. I'm assuming that there's rubber pads that will have worn away/hardened over the years that are stopping it from playing back? Manually spinning the tape confirms that the amp is working as sound comes out loud and clear. More importantly, after a couple of minutes of being turned on, a strong burning smell develops, much like the smell that an iron makes when you use it. I noticed that the 'Record Level' tube doesn't light up, but one tiny yellow spark slowly lights up as the burning smell starts - is this a failed tube or something more sinister? I'd really like to give this deck a thorough service and finally get to enjoy using it. The case is really clean, as is the deck on top. If anyone can advise on how I should tackle these issues and perhaps point me in the direction of a service manual for it (I've had a look on Google and can't seem to find anything), that would be really appreciated. Thanks in advance, Cameron.

14th Apr 2017, 7:40 pm	#2
Cameron Retired Dormant Member Join Date: Oct 2010 Location: Nottingham, Nottinghamshire, UK. Posts: 56	Re: Brenell Mk5 Restoration On closer inspection, the Mullard EM87 tube looks to have expired inside. There's a black burn mark in the side of it. I think this is the source of the burning smell. All the capacitors look visually okay, I'm not sure how to test them otherwise though.

14th Apr 2017, 7:42 pm	#3
Boater Sam Banned Join Date: Dec 2013 Location: Middlewich, Cheshire, UK. & Winter in the Philippines. Posts: 3,897	Re: Brenell Mk5 Restoration Not really a good idea to just plug it in and hope, you could be doing a lot of damage. Have a read of the "stickies" on this site about starting renovations. To help you we need to know your level of ability, experience and what tools/test equipment you can access. There are posts re Brenells on here, do a search in the box at the top. Someone will find the service info, there is a website, brenelltape.co.uk.websitebuilder.prositehosting.co .uk/ Sam.

14th Apr 2017, 8:18 pm	#4
Cameron Retired Dormant Member Join Date: Oct 2010 Location: Nottingham, Nottinghamshire, UK. Posts: 56	Re: Brenell Mk5 Restoration Thanks for your reply Sam, I just trusted that it was okay to use because the person who sold it me on eBay had it pictured plugged in with the lights on and said it was 100% fully working. I should have queried it at the time, but guessed maybe something got damaged in the post. I've restored a Philips EL3515 before with new pads, new belts, demagentizing the heads etc... and then a Sony TC-377 which was a similar job. Both done with kits on eBay. I have electrical screwdrivers, a multimeter, tape head demagnetizer, soldering iron but that's about it. I can deal with most of the issues that the decks have given me, but I'm not brilliant with circuitry work. I've already had a good search on the forum about Brenells, but can't seem to find a topic describing the problems that I'm having with mine. I've seen the website too, it's helped me date my unit to 1964-1966. But I haven't found any information about servicing on there.

14th Apr 2017, 9:17 pm	#5
Boater Sam Banned Join Date: Dec 2013 Location: Middlewich, Cheshire, UK. & Winter in the Philippines. Posts: 3,897	Re: Brenell Mk5 Restoration EM87 is a valve, electrofluorecent display, and they can't make a smell unless smashed. The "burn" mark could just be the getter inside the envelope, normal. This could be a red herring. Valves are very reliable and providing they still have a vacuum don't age if unused. Before connecting to any power, look for a resistor that has got hot, smell around any motor, transformer, wound components. Any bulging capacitors? Eyes, nose and ears find many faults. It is possible that it was working but age has caught up with a capacitor and it has gone electrically leaky. Establish a positive fault finding sequence, without guessing, to achieve a solution. You need to find a circuit diagram at least, is the Brenell site any help? Sam.

14th Apr 2017, 9:23 pm	#6
Boater Sam Banned Join Date: Dec 2013 Location: Middlewich, Cheshire, UK. & Winter in the Philippines. Posts: 3,897	Re: Brenell Mk5 Restoration Is this your unit? If so you can download the circuit diagram (they send it to your email) free but don't publish it anywhere please. http://www.radiomuseum.org/r/brennel...amplifier.html Sam.

15th Apr 2017, 6:24 am	#7
Diabolical Artificer Dekatron Join Date: Jul 2009 Location: Sleaford, Lincs. UK. Posts: 7,657	Re: Brenell Mk5 Restoration Schematics and useful info available here - http://www.schimmel.talktalk.net/tap...ne/brenell.htm Sams right, never a good idea to wing it by plugging vintage anything straight off the main's, which is probably what the original seller did; all a lit light bulb tells you is that there is power out of the main's tfmr and the lightbulb works. To start with a warning THERE ARE VOLTAGES PRESENT INSIDE YOUR BRENNEL THAT CAN KILL you might be aware of this, but we don't know that, so good to let you know. Secondly, there are various Brennel Mk5's, mono, stereo version's etc. As Sam says there are "stickies" which are informative threads that deal with some aspects of vintage gear restoration. For instance if you use the "search this website" box at the top of the page to find threads on how to test a capacitor, you get something like this - https://cse.google.com/cse?cx=008872...ors&gsc.page=1 Before you power it up again make a lamp limiter, instruction's here - http://www.vintage-radio.com/projects/lamp-limiter.html this will help reduce any damage by limiting current to your machine and give a visual indication of it's "health" Next you need to do a good visual inspection, test and replace any faulty capacitors, especially coupling caps. When your at that point we can go further. Lastly, see if the motors are turning or even better see if you have 240v at the motors and that the motor run caps are ok. Good luck, Andy. __________________ Curiosity hasn't killed this cat...so far.

15th Apr 2017, 3:00 pm	#8
Cameron Retired Dormant Member Join Date: Oct 2010 Location: Nottingham, Nottinghamshire, UK. Posts: 56	Re: Brenell Mk5 Restoration Thanks both for your replies. Mine is a slightly later Brenell Mk5 than the one that Sam posted, this is a photo of an identical model to mine: http://files.websitebuilder.prositeh.../mk5s2reel.jpg. It's mono, with the original tape heads, though it has the upgraded capstan to allow it to play back at 15ips. I've come across the Brenell website many times, however this is the first time I've noticed the circuit diagrams. So thanks for pointing me towards them. The motors definitely work, the FF/RW works perfectly, but you can hear the reel tables slipping on playback. I have to admit, this is getting a little bit over my head with this now. I can cope with mechanicals but electricity isn't my friend - I've been vexed fitting electric ignition to my Rover P6 this weekend, so this kind of circuitry is beyond my capabilities for now! I'd love to learn, but I learn best watching someone else and then having a go. I can't find any videos on YouTube about restoring a Brenell. Are there any specialist repairers near to Derby/Nottingham? That's where I've just moved to. There was a guy in Leeds where I lived before but it seems a long way to go to take a tape deck for repair. But for now I'll take the deck apart again and visually inspect the capacitors to see if there's anything visually amiss. Thanks again.

15th Apr 2017, 9:56 pm	#9
Tractorfan Dekatron Join Date: Mar 2008 Location: St. Frajou, l'Isle en Dodon, Haute Garonne, France.(Previously: Ellesmere Port, Cheshire, UK.) Posts: 3,182	Re: Brenell Mk5 Restoration Hi, The 'burn' mark is normal inside a valve and is the getter that has done its stuff and mopped up any stray molecules of gas left behind during evacuation. If you suspect that there's a short within it (unlikely), you can simply unplug it and see if the burning smell stops. Are you sure that the 'tiny yellow spark' isn't just the heater warming up? It's about half way up the valve, and right at the back. Forgive me if I'm stating the obvious. Cheers, Pete. __________________ "Hello?, Yes, I'm on the train, I might lose the signal soon as we're just going into a tunn..." Last edited by Tractorfan; 15th Apr 2017 at 10:00 pm. Reason: Extra worms.

15th Apr 2017, 10:12 pm	#10
Boater Sam Banned Join Date: Dec 2013 Location: Middlewich, Cheshire, UK. & Winter in the Philippines. Posts: 3,897	Re: Brenell Mk5 Restoration There is a section on this forum to request members who repair or mentor. If you can't find anything obvious, post for help in this section, there are lots of members around you.

16th Apr 2017, 5:28 am	#11
Diabolical Artificer Dekatron Join Date: Jul 2009 Location: Sleaford, Lincs. UK. Posts: 7,657	Re: Brenell Mk5 Restoration Your welcome to pop over here if it helps Cameron, it's about an hours drive. I have a Brennel 5 I need to sort, happy to have a Brennel fixing day. Drop us a PM if interested. Andy. __________________ Curiosity hasn't killed this cat...so far.

16th Apr 2017, 11:59 am	#12
Boater Sam Banned Join Date: Dec 2013 Location: Middlewich, Cheshire, UK. & Winter in the Philippines. Posts: 3,897	Re: Brenell Mk5 Restoration Now there is an offer not to be missed Cameron, a day with the Master on the bench. You will learn more in that day than a month asking on the forum, bet there are bacon butties too.

17th Apr 2017, 5:05 am	#13
Diabolical Artificer Dekatron Join Date: Jul 2009 Location: Sleaford, Lincs. UK. Posts: 7,657	Re: Brenell Mk5 Restoration Hardly a Master Sam, just a bit more along than Cameron. Sorry no bacon butty's either, though Molly won't mind you pinching a few of her sausages if your inclined. : ) A. __________________ Curiosity hasn't killed this cat...so far.

6th May 2017, 7:15 am	#14
Old Dave Retired Dormant Member Join Date: May 2017 Location: Nowra, New South wales, Australia Posts: 1	Re: Brenell Mk5 Restoration Hi All, Tacking onto Cameron's post because it's easier that typing it all out again. I pulled my Dad's old Brenell Mk 5 (Series 1? with white/bone head covers) from the garage while waiting on parts for another machine. Following Boater Sams advice (Before connecting to any power, look for a resistor that has got hot, smell around any motor, transformer, wound components. Any bulging capacitors? Eyes, nose and ears find many faults) I found the one he was looking for! It measures 770 ohms out of circuit. I powered it up and the results are pretty much the same as Cameron's. Replaced the counter belts. Flywheel somewhat reluctant when in Playback. What was that about a resistor? Suspect resistor is getting hot, >60 degrees C. Power off, take photo's & close the box until electrical issues are resolved. Picture added. I can't read anything on the resistor and am in need of the schematics & service manual. Help please? Thanks, Dave Attached Thumbnails

10th May 2017, 12:08 pm	#15
jamesperrett Octode Join Date: May 2007 Location: Liss, Hampshire, UK. Posts: 1,873	Re: Brenell Mk5 Restoration If you are talking about that grey resistor in the front of the photo then it is supposed to get fairly hot - they wouldn't have fitted quite such a large one if it they didn't expect it to heat up. As far as I can remember, it is connected to the take up motor circuit in play mode in order to reduce the current through the take up motor so it should only get hot when the deck is in play mode.