From: cd6699@notformail.com   
      
   On Thu, 11 Dec 2025 10:57:39 +0000, liz@poppyrecords.invalid.invalid   
   (Liz Tuddenham) wrote:   
      
   >Cursitor Doom  wrote:   
   >   
   >> On Wed, 10 Dec 2025 21:38:18 -0500, ehsjr  wrote:   
   >>   
   >> >On 12/10/2025 6:14 PM, Cursitor Doom wrote:   
   >> >> On Wed, 10 Dec 2025 21:58:21 +0000, liz@poppyrecords.invalid.invalid   
   >> >> (Liz Tuddenham) wrote:   
   >> >>   
   >> >>> Cursitor Doom  wrote:   
   >> >>>   
   >> >>> [...]   
   >> >>>> He said, "Give the heads a good clean,   
   >> >>>> then." I said, "They don't look dirty." He said, "Give 'em a good   
   >> >>>> clean anyway and see if that fixes it." So I did (not having any faith   
   >> >>>> it would help in the least, however). Nevertheless, full recording was   
   >> >>>> instantly restored!   
   >> >>>   
   >> >>> I asked if you had cleaned the heads right at the beginning of this   
   >> >>> thread.  The tineiest of gaps between the head and the tape can have   
   >> >>> quite drastic effects on reproduction and even worse ones on recording.   
   >> >>   
   >> >> I'm not seeing it for some reason. Can you give me the message ID?   
   >> >   
   >> >On Wed, 26 Nov 2025 09:55:24 +0000, liz@poppyrecords.invalid.invalid   
   >> >(Liz Tuddenham) wrote:   
   >> >   
   >> > > Cursitor Doom  wrote:   
   >> > >   
   >> > >> I've been trying to trace an issue with a Uher tape deck in respect of   
   >> > >> extremely  low audio gain during recording. I was delighted when I   
   >> > >> spotted a resistor in the AGC section with a tiny blow-hole half way   
   >> > >> down its body. I was able to confirm this when I removed it for   
   >> > >> examination under a stereoscope. There was even a bulge under the hole   
   >> > >> where some pressure had clearly built-up immediately prior to the   
   >> > >> blow.'Easy fix!' I thought; 5 minutes and it's done. However, I was   
   >> > >> baffled when it tested spot-on its 1200 intended ohms! WTF?? Something   
   >> > >> must have pulled excess current through that component and the obvious   
   >> > >> culprit was the BJT it was the series resistor for. However, once   
   >> > >> again, it tested fine! I just never have encountered an outcome like   
   >> > >> that before. Anyone had similar?   
   >> > >   
   >> > > Have you cleaned the tape heads?   
   >> >   
   >> >Yes, but not for that reason as the fault just suddenly manifested out   
   >> >of nowhere.   
   >>   
   >>   
   >> Much oblig'd. Clearly what happened here is that in the pile of old   
   >> tapes I was working through, there was a section of tape that was   
   >> shedding oxide (very common with old tapes) which undid all the prior   
   >> cleaning effort. I did mention subsequently that when I tried the   
   >> suggestion from the Ferrograph guy I was expecting no positive outcome   
   >> as the heads *appeared* perfectly clean to me. Just goes to show how a   
   >> tiny bit of invisible foulage can throw a real spanner in the works   
   >> for the unwary. Lesson learned!   
   >   
   >About 6 months ago I was asked by a local dancing school if I still had   
   >the master tape of a show where I had done the sound 20 years ago.   
   >After spending an evening sorting through piles of tapes stored in a   
   >disused lavatory (Yes, really!) we found it.  I laced it up on one of my   
   >Ferrographs (Logic 7) and the sound quality immediately deteriorated to   
   >rubbish.   
      
   Knowing what I now know and never having handled 40+ year old tapes   
   before, I can well believe it. The F'graph I recently had serviced is   
   a Logic 7 as well, BTW.   
      
   >We played the tape for long enough to identify that it was the correct   
   >one, then I had to spend the following evening cleaning up the required   
   >5-minute segment.  I wound the of tape backwards and forwards through a   
   >fold of soft cloth, picking up loads of debris at each pass.   
      
   According to the nerds on Tapeheads, before we play an old tape we   
   should bake it beforehand - yes, really - and digitize it upon first   
   play then bin it for the sake of our machines!   
      
   >Eventually i was able to play it, stopping and cleaning the heads and   
   >the guides several times.  If you don't clean the guides as well as all   
   >the heads, including the erase head, even a clean tape can drag   
   >particles into the recording and playback heads.  Finally I edited the   
   >good bits together, burnt them onto a CDR and sent them to the dancing   
   >school.   
      
   Yes, you would have to do the entire visible/accessible tape transport   
   mechanism or it won't have the desired effect for that reason. I find   
   it unbelievable that heads that *appear* spotless can refuse to work   
   properly until freshly cleaned again. How many picograms of crap does   
   it take to mess things up? Can't be many!   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)