Citroen (Freeman) 550 tape recorder- bad capacitor? - Page 2 - UK Vintage Radio Repair and Restoration Discussion Forum

camtechman · 19th May 2017, 7:38 pm

Not that this will help you with your problem but below are pics of a "Comet" branded version.

This version runs on two packs of 6 AA batteries (i.e. 9v each)

Also, as will see from pic 4 this may be an earlier version as there are no established pcb's and all components are mounted on perforated paxolin and hard wired/soldered.

Forgot ths pic:

julie_m · 19th May 2017, 9:19 pm

Measuring a tape head with a meter can be bad; though not because of any risk of burning out the coil (even a cheap analogue meter only ever puts out a maximum of 1 mA) but because of the risk of leaving the core magnetised. This will cause your tapes to be partially erased -- they will literally get very slightly quieter and quieter every time you listen to them.

A DC-energised erase head (such as yours) is definitely safe to measure with a meter, because it is designed to pass rather more than 1 mA of DC continuously and retain no magnetism. An AC-energised erase head will tend to self-demagnetise in operation. A record/play head should only be measured with a digital meter, a high Ω/V analogue meter on its most sensitive range or an AC bridge. Even then, it's probably best to demagnetise it afterwards, because it's such a nasty, subtle fault.

ct92404 · 20th May 2017, 3:55 am

camtechman, that's really interesting - that tape recorder looks pretty much identical to mine. Except of course that the circuit is wired differently, and the colors are different. But the layout is exactly the same. I wonder why that one needed so many batteries though?!

I think at this point, I've probably gone as far as I can. I couldn't find anything wrong with the wiring going to the erase head, so the problem must be the head itself. Also, I just noticed that one of the screws for the top plate is stripped and I can't get it off, so I can't get access to the inside of the front (like pic 4 in camtechman's post). I guess I could drill that screw out, but that's not something I really want to get into right now. And I don't even have a replacement head, anyway.

The tape recorder does play and record, at least. I do have several other reel-to-reel tape recorders, and I can just erase tapes on one of them if I want to re-use a tape. It would be a little annoying and a hassle, but it's not the end of the world. I can always have this one as a nice display and still play around with it. So I'm kind of thinking that at this point it might be best for me to just leave it alone. I'm afraid that if I mess with it too much, I might really screw it up and it won't work at all anymore. If I can get another erase head for it, maybe I'll try again sometime.

Thank you for all your help, everyone! At least we were able to narrow down what the likely problem is - the erase head. I definitely learned a lot from this!

19th May 2017, 7:38 pm	#21
camtechman Nonode Join Date: Jan 2008 Location: Milton Keynes, Bucks. UK. Posts: 2,552	Re: Citroen (Freeman) 550 tape recorder- bad capacitor? Not that this will help you with your problem but below are pics of a "Comet" branded version. This version runs on two packs of 6 AA batteries (i.e. 9v each) Also, as will see from pic 4 this may be an earlier version as there are no established pcb's and all components are mounted on perforated paxolin and hard wired/soldered. Forgot ths pic: Attached Thumbnails __________________ When I die, please don't let my Wife sell my collection for the amount I told her I paid for it!

19th May 2017, 9:19 pm	#22
julie_m Dekatron Join Date: May 2008 Location: Derby, UK. Posts: 7,735	Re: Citroen (Freeman) 550 tape recorder- bad capacitor? Measuring a tape head with a meter can be bad; though not because of any risk of burning out the coil (even a cheap analogue meter only ever puts out a maximum of 1 mA) but because of the risk of leaving the core magnetised. This will cause your tapes to be partially erased -- they will literally get very slightly quieter and quieter every time you listen to them. A DC-energised erase head (such as yours) is definitely safe to measure with a meter, because it is designed to pass rather more than 1 mA of DC continuously and retain no magnetism. An AC-energised erase head will tend to self-demagnetise in operation. A record/play head should only be measured with a digital meter, a high Ω/V analogue meter on its most sensitive range or an AC bridge. Even then, it's probably best to demagnetise it afterwards, because it's such a nasty, subtle fault. __________________ If I have seen further than others, it is because I was standing on a pile of failed experiments.

20th May 2017, 3:55 am	#23
ct92404 Pentode Join Date: Sep 2015 Location: San Bernardino, California, USA. Posts: 101	Re: Citroen (Freeman) 550 tape recorder- bad capacitor? camtechman, that's really interesting - that tape recorder looks pretty much identical to mine. Except of course that the circuit is wired differently, and the colors are different. But the layout is exactly the same. I wonder why that one needed so many batteries though?! I think at this point, I've probably gone as far as I can. I couldn't find anything wrong with the wiring going to the erase head, so the problem must be the head itself. Also, I just noticed that one of the screws for the top plate is stripped and I can't get it off, so I can't get access to the inside of the front (like pic 4 in camtechman's post). I guess I could drill that screw out, but that's not something I really want to get into right now. And I don't even have a replacement head, anyway. The tape recorder does play and record, at least. I do have several other reel-to-reel tape recorders, and I can just erase tapes on one of them if I want to re-use a tape. It would be a little annoying and a hassle, but it's not the end of the world. I can always have this one as a nice display and still play around with it. So I'm kind of thinking that at this point it might be best for me to just leave it alone. I'm afraid that if I mess with it too much, I might really screw it up and it won't work at all anymore. If I can get another erase head for it, maybe I'll try again sometime. Thank you for all your help, everyone! At least we were able to narrow down what the likely problem is - the erase head. I definitely learned a lot from this!