Hello Fellow retro tech enthusiasts;N1700 Fault Assistance
Not a hobbyist as such since I have been in the TV repair trade since I started washing vans on a Saturday aged 11 and gradually was allowed into the workshop. There I began what was to be my education in electronics so to speak ..and was helping with repairs by age 15.
That company eventually sold out when the owners retired ..so I went self employed and am now 64 years old but still doing repairs though I have MS and my eyesight is failing. So during lockdown I had much time on my hands so raided the treasures stored in my loft.
Restored many 8 bit computers a sharp reel to reel and various VCRs amongst these was an old N1700 which I want to live again as the tapes have family stuff on them which I want to eventually digitise.
I rather suspect some of these tapes were recorded on a modded N1500 ..which would have had the machined pulley for longer play and 1700 heads fitted so I suspect these tapes would play on the n1700 but incorrect speed and poor tracking. Nonetheless the first challenge is to get the N1700 up to spec.
I now have it functional and the heads look ok but FF and REW are problematic rarely completing either without switching off. I have changed all belts ..so I am at a loss.
Any help with this project would be appreciated.
Hi Viper, welcome to the forum. First things first. I take it the threading is working? Equally that the 30 second head protection delay is working prior to you selecting any function such as play, REW or FF?
Threading/lacing is fine the 30 second delay is working fine. I do actually get an image unlocked of course as I have yet to find a genuine 1700 recording. Rew and FF work the process just slows before reaching full spool transfer of tape thus movement halts and the tape auto unlaces. Sometimes it is possible to restart the process and get a bit further but this just slows and stops again. Play on the other hand completes without incident transferring all tape to the take up spool but on attempting to rewind it, it slows and stops. If it were a VHS machine ..chances are youd point a finger at the idler.
Excellent that extra info is very helpful. This sounds like the same problem I had with one of my N1700's. You need to do some voltage checks in the circuits some of those lovely Philips modules are involved, oh and the friction motor. Unfortunately my workshop is totally shutdown due to major extension works. It should be up and running in the next couple of weeks but I cannot access my manuals etc nor scan them. If I remember rightly you're looking for 25V, 11V and 7V when performing the Wind Rewind but I cannot remember which.
Welcome from me as well, can’t help with the VCR, only saw one N1700, repaired a few VHS and BetaMax but they were very new and simple faults. So many years ago.
I will leave it to others on the forum.
I guess I could use a copy of the service manual then.
It's lot of pages. I'm not sure where my copy is, but it's a genuine Philips repair manual, and it's in two volumes plus addenda.
Many thanks for the warm welcome guys.
Anyhoo.. back to the rew/ff problem, I am beginning to suspect this is a mechanical issue rather than electrical. I lifted the friction motor and applied a little oil, tricky getting it under the motor pulley but before replacing the motor chose to go for a slightly smaller diameter belt (tighter) so a bit more drive?
This does appear to have helped as I can now rewind a 1 hour tape from start to finish and then fast forward the same tape to the end. It rarely does this in one pass ..but 2 or 3 re-starts is better than before where the process would continually cut out causing me to give up.
Maybe the motor itself (bearings)?
Good news, managed to find a mauritron copy of the 1700 manual on e-bay.
I stopped buying from them years ago as I found mostly all their "copies" to be expensive and of substandard quality. Hopefully yours will be an exception.
A whole new problem has reared it's head, the N1700 now refuses to thread up a tape i.e. the heads spin but the loading ring/guide assembly no longer rotates. It doesn't appear to a be a motor issue as the worm drive from the loading motor does turn.
I have got it in my head that it is possibly related to this gear assembly exploded diagram ref 256. I have disassembled this mini planet gear device to look for missing teeth on cogs or cracks in the plastic though don't see anything wrong.
I guess it is possible the main shaft running through top to bottom is not tight enough in the plastic housing thus drive doesn't make it from motor to loading ring. I need your advice again Crusty, are these mini gear assemblies reliable or do they have know issues? And chances of finding a replacement if it is faulty is near zero.
Do they have known issues and can they be fixed ?
Hi Viper, I've not had issues with that gear assembly on my machines, unlike my N1500's where the threading drive is a notorious failure point along with the hellish lacing string!
As your gears seem to be OK it can't hurt to check over the threading circuit to make sure nothing has gone awry there (see below). At least it will eliminate the electrical and confirm mechanical or vice-versa.
I know you love restoring old TVs just found what I think are a couple of new old stock clone copies of Ferguson 3500 EHT units in my loft, any use to you buddy ?
Hi Viper, They would be most useful, as you may have seen from my collection I have a lot of 3k/3.5K sets to maintain. Let me know how much I owe including the postage and how you would like paying (PayPal/Bank transfer?). We can take this off-line to private, I'll send you a private message.
By the way, your act of kindness in offering up the triplers, has unlocked access for you to the data library. 👍 You can access this service via the hot link bubbles at the top of the page.
@crustytv The triplers are packaged up and am expecting a visit from my niece to pick up some digitised VHS stuff I did for her during the dreaded lockdown.
I am going to ask her to post it to you at her convenience.
Are these mini gear assemblies reliable or do they have know issues ?
..and chances of finding a replacement if it is faulty is near zero.
Do they have known issues and can they be fixed ?
I have nine of these machines, though not all working right now, but can safely say that when they did, I never once encountered any faulty mechanicals in the threading department. I remember once encountering a strange threading problem, or at least, Granddad did. It was a rush job for Christmas, and the fault was cured by an impromptu replacement of the PSU board. Sad part is, I don't remember (after 40 odd years) what the fault was, but the PSU was repaired and went back into service.
As for known issues, I know of none, but of course, time has moved on and what was reliable 30~40 years ago may not be today. Chances of finding a replacement are practically nil, but, on very rare occasions I have seen used parts for sale via eBay, so there must be some machines that are being dismantled, somewhere.
One problem that does occur with these machines, or moreover, several that all relate, would be the cassettes themselves. Repeated winding and rewinding is not advised because this can cause the tape to run unevenly onto the spools, effectively making the tape wider and causing it to bind up. Similarly, tapes that have suffered dampness will bind and cause threading, winding, rewinding and playing issues. To borrow an American aphorism, the tape needs to be "crispy critter" dry. - I will be baking mine when restoration gets underway, in earnest. Also, it is possible for the tape to become excessively tightly wound, which brings with it a number of issues.
@katie-bush Yes indeed Kate.
I am familiar with sticky tape shedding and I acquired a food dehydrator to bake all my tapes for 48 hours at 50 deg-C Sadly I can only do 4 at a time. lol
I may have some good news soon regarding the threading problem It is gearbox related. Somehow the bottom cog of the gearbox is riding high with respect to the toothed circular loading ring thus drive isn't being transferred. At the moment I'm cleaning the loading ring and guides and applying a little lithium grease before fitting a couple of thin washers to force that gearbox down and stop it lifting and riding high above the loading ring.
Basically too much play over the years I suspect and the loading motor worm drive top plate doesn't apply enough downward pressure in the right places. A bit of a bodge sure but thin spacers seem to fix the problem.
Well, that's a new one on me! But as we know, nothing lasts forever, and what we might never even think of as a likely then, could be the very thing we need to look at today.
With regard to grease, I use EP-2. It's a high pressure grease with an excellent film resilience, and moisture exclusion properties. In some instances, "red rubber grease" (aka brake grease) can be useful. It's silicon based and is waterproof, but some versions seem to dry out eventually, so may not be ideal for parts in constant motion. Also of great benefit, I discovered a Teflon based lubricating oil from "Wilko" which is excellent for motor and spindle bushings. I use it a lot for fans, and in tiny ball race bearings.