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-   -   Philips N1700 playing tapes from a modded N1500 ? (https://www.vintage-radio.net/forum/showthread.php?t=172669)

ViperSan 1st Nov 2020 2:06 am

Philips N1700 playing tapes from a modded N1500 ?
 
Being in lockdown has given me time to investigate what I have stored in my loft over the years..
Well I uncovered a box of VCR tapes these are currently being baked at 50 deg C ...
I also dug out a philips n1700 in need of restoration..a project suitable for lockdown.
If I restore the machine to working condition ..then obviously I could re-use the tapes...but...I would like to see what's on them.
This I know is going to be an issue as if memory doesn't fail me ...they were recorded on a modified n1500.
I remember sending the capstan pulley for machining...and replacing the head drum with a 1700 head drum.
This made for a hybrid machine with double tape capacity by reducing speed.
my memory is a bit hazey here but I think the mod was in "Television" sometime in the 80s
I'm assuming then that these tapes might possibly play back on a 1700 ?
..which would have the correct head drum ...but might not run at the right speed due to the machined pulley not being reduced accurately.
also ...tracking could be an issue as the audio/tracking head was the original 1500 one..which I guess is different to that used in a 1700.
Is it possible that a 1700 could play these tapes ?
..and if so ..what would need to be changed tweaked or modified.
any advice from experts would be appreciated.
rgds
VS

atsampson 1st Nov 2020 2:55 am

Re: Philips n1700 playing tapes from a modded n1500 ?
 
There's quite a bit of discussion in 1978 issues of Television about modifying N1500s to be (partly or fully) N1700 compatible - e.g. "Longer VCR Playing Time" in Feb 1978, and a letter on p526 of Aug 1978 that seems to have a fairly complete description of the mods. World Radio History has these issues (but is missing Sep/Oct 1978, unfortunately).

Iontrap 1st Nov 2020 9:57 am

Re: Philips n1700 playing tapes from a modded n1500 ?
 
This brings back memories. After the N1500 Philips brought out the N1502.
Very similar to the 1700 with DC motors and non of that lacing cord loading business whilst still being 1500 format.
Seem to remember an article in Television converting a 1502 up to 1700 format by reducing the capstan and swapping heads.
The problem you will have is 1700 format used slant azimuth heads so it doesn't use guard bands unlike a 1500 head which does not use slant azimuth so incompatible.
You can at least get your machine working and at least the audio may tell you if anything interesting on tape.
I did the Television mod which extended play on a 1700. Also fitted crispener module from a 1500.
Like the head mod any alteration means machine unlikely to play tapes satisfactorily unless they were recorded on that machine.
Its a long time ago so I hope I recall all this correctly!

ViperSan 1st Nov 2020 11:36 am

Re: Philips n1700 playing tapes from a modded n1500 ?
 
Obviously I wouldn't expect perfect playback..as you rightly say ..only the orginal modded machine can do this...which sadly no longer exists.
but I figured that since the tapes were recorded on a modded machine which would have had 1700 heads fitted ...they might stand a chance of some sort of image on a genuine 1700 ...even though speed and tracking would still be an issue.
rgds
VS


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