[Closed] Philips N1500; No Colour, Distorted Sound
I'm not sure if this is the right Forum to post this but I've recently joined the site and have been reading the repair threads here on the Philips N1500 with much interest.
I have one of these machines myself which was given to me by a secondary school where I used to work. Approx 5 years ago it was serviced by an ex Radio Rentals engineer called Ned, a good friend, who gave it a really good going over and replaced the loading mechanism.
I set up and run the machine every couple of months just to keep it going, but around a month ago, the colour suddenly changed to Black and White. Then a few days later the sound level became distorted.
I know a bit about electronics as I've done a few Reel to Reel repairs, and have repaired a Ferguson 3v32 (caps and belts replacement), but I don't know quite where to start with the N1500. The circuit boards aren't clearly marked with any obvious identity, and the only service manual I could find was in Dutch!
Sadly Ned is no longer with us to help me with the faults 🙁
I'm hoping someone here can shed some light for me!
I've uploaded a video of the N1500 with it's problems to my YT channel:
Hi and welcome to the forum.
These players are notoriously difficult to work on for a number of reasons, no component markings, boards difficult to remove due to being hard-wired in and of course all those damn plugin modules. Also, not forgetting about those horrendous gooey belts and yes the awful fragile drum lacing. I had one of mine break on me and it was a nightmare to re-lace. The lack of player specific parts can be a problem unless you buy a cadaver to rob.
VCR repair whatever the format, be it early Philips, VHS, Betamax are complex pieces of consumer equipment and are not for the faint-hearted to tackle. This is not to say they cannot be fixed because they can, it requires patience and perseverance and a logical mind along with a dose of mechanical-mindedness. The key is knowing when to take a break, I have a couple of these players on the go and in various states of repair, one further ahead than the other. One I'm blogging about is an ex BBC unit. it can be found here.
OK, one thing at a time, let's start with the "no colour". Out of interest is the colour indicator La2 lit?
If not, you'll need to take some voltages, the first the place to start is panel 3 checking u1506. Panel 3 is a daughter board directly soldered vertically into Panel 2. A scope would be good to have, though not essential yet, so you can check expected waveforms are present. Check the OSC voltages here are correct at U1506 sample points and into TS1411 Osc ctrl, also the sub carrier output TS1410. The output of which departs via 80/81(7BU10) and should appear at 4BU5/ C221, so don't forget it arrives at the other end, check there.
If La2 is lit then, there are a whole raft of other components to check and voltages to be verified to narrow it down, an oscilloscope would also be beneficial to have to hand. The Philips fault-finding guide should help you make a start with this first problem, maybe you'll get lucky and it will be the OSC.
Once colour is sorted only then move on to the distorted sound (Panel 2). On the positive side you have a good black and white picture, so there's not a lot wrong, it's just a matter of donning your Sherlock hat, and approaching it methodically.
I do have the full English service manual that can be made available to you. However, over the years I've had no end of folk turn up take free data only never to be seen or heard of again, prime example last week here.
So stick around, ask questions, you'll certainly get help from all the great guy's and the one girl at Radios-TV Vrat.
Once you've shown good faith and that you wish to be part of this great community, you'll get access and more to all you need. I'm often criticised for this stance, mainly by armchair admins who never actually got of their arse to add anything, that never buy the data in the first place, nor time spent on scanning or paying to host it. Radios-TV Vrat is no different to the other forums where you either have to pay or make a number of posts before getting access.
In the meantime ask all the questions you like, every bit of assistance/advice you need will be offered to help you get started. Snippets of diagrams will be posted in your thread as you progress, including the likes above to aid you in your fault-finding quest.
Yes welcome, I had no dealings with this VCR, or the newer N1700. VCR machines were just becoming popular at the end of the 70’s when I left the trade so I have no suggestions.
Others like Chris do have experience and hopefully you will get the help required to get it working well.
@crustytv Hi again, and thanks for getting back to me.
I can confirm that when the VCR is On in STANDBY (ready to play a tape) the Colour Lamp La2 is LIT and there is Colour on the RF input signal. I've tested this by hooking up a DVD player through an RF Modulator and tuning that in to the VCR. Nice clear picture!
So it must just be a colour error on the playback. I'll start my investigations tomorrow and keep you updated. It's good to be learning about something new too, as I'm familiar with the Ferguson/Thorn models, but not the N1500. I'll also dig out the oscilloscope too, although I haven't used that for a few years!
I have inherited a few service manuals from my friend Ned when I was repairing the Ferguson VCR which I'll be happy to scan and share with the community here. After all we're all here to share our knowledge and help eachother.
Many thanks for your help so far 🙂
Hi, According to my notes I did have a brief encounter with the directors N1500 back in 1985 with a 'no colour' fault on playback. It also had servo issues which turned out to be gummy motor bearings due to being stored in his loft for five years, drop everything and do an instant repair!
But I digress and if power supplies check out OK, two modules to look at are U66 (VCO and divide by 36) and U67 (phase/frequency control). Phase and frequency lock of the 562.5kHz voltage controlled oscillator in module U66 was not working and a fault had occurred in one two divide by 6 circuits. There was no output on U66 pin 13 to provide the 15.625kHz control feedback. Transistor TS6 (BC149) had an open circuit base-emitter. Back then 'Lockfit' transistors didn't have quite the same reputation of failing as they do now.
So a quick check would be to scope the output waveform on pin13 U66 which should have a 64μs period, 1μs duty cycle
Incidentally the 'important' tape turned out to be Top Of The Pops 1975!
Could Philips have used any more six references in this circuit, U66, TS6, divide by 6, divide by 36 ?
Just an update with the N1500. . .I've dug out the scope and tested the voltages in the Clock Area Panel 3 and Panel 2. Amazingly all readings were good. I then tested resistors etc with a meter and they were also good except for a transistor BC148 which wasn't giving a reading. I replaced this, but still had the same problem with the picture and sound.
I'm going to move on and look at U66 and U67 as suggested by @marconi_mpt4, paying attention to some of the transistors, and checking them through. These are tiny boards so I'll definately need my specs for these!
Last night I set up and tested units U66 and U67, and although there was a slight hairline crack on the top edge of U66, everything was fine and output readings were good, including pin13 as suggested by @marconi_mpt4
This hairline crack got me thinking that there could be the possibility of a cracked PCB board somewhere, so I'll be inspecting them all to check next time I set everything up.
It must have taken forever to build these machines, as they are really well put together, and the amount of soldering and wires that are running all over the place are quite something when compared to VCRs 10 years down the line!
Well after a somewhat manic few days for me, I managed to find a good two days to sit down with the N1500 and give it a good going over.
Unfortunately after a few hours of playing with the scope, the scope itself decided to start playing up, giving inaccurate readings on components it gave good readings on before! This then got me thinking. . .has the scope been playing up all the time? Have I been getting good readings when I should have been getting bad ones?!
I carried on with a 'visual' check and noticed that one of the circuit boards (I think it's the servo board) had a crack in the corner and what appeared to be a wire joining the track back together. I took the wire off, and it made no difference to the sound and picture issue, so I put it back on.
Without a reliable scope, and the necessary equipment, I'm sorry to say that I have called it a day on this project. Hopefully it will go to a good home when it goes live on a 'well known' auction site.
On another note, last week I went to collect a few bits and pieces which belonged to my old friend Ned. I came away with some Used Spares for the Philips 'N' machines, a SONY 1810 UMATIC Machine, a Philips N1502 and a EUMIG 610 Cine Film Projector, so I'll be looking at these for future projects.
I have taken some photo's of the N1500, which I will upload, and it really will be a shame to see it go. I've grown rather attached to it!
Hi Craig, I spotted that on e-bay and thought it was yours. Shame you decided to give up but I understand your reasons. I may just have a punt on it as I've a soft spot for N15K machines and have gathered quite a few spares. Who knows, If I'm lucky you might just see the repair feature on my YouTube channel and/or in one of my blogs.
On another note, it sounds like you've got yourself a nice little haul there with the N1502, Sony U-matic and other elderly machines. A word of caution though, all these VCR's are likely to present a challenge and rarely a simple fix. They're likely way beyond a simple rubber change and re-grease, as you've discovered. I pointed this out in my 2nd post (see quoted snippet below) of this thread.
VCR repair whatever the format, be it early Philips, VHS, Betamax are complex pieces of consumer equipment and are not for the faint-hearted to tackle. This is not to say they cannot be fixed because they can, it requires patience and perseverance
By way of example, if you've not looked at these (links below) before, perhaps they might give you some ideas or encouragement. Both my N1500s are still being worked on. Machine 1, I initially got working only to have SK401 & SK402 fail, I managed to source new but have not yet finished the repair. N1500 machine 2, I recently got the protection circuit working after finding half of the 4 diode bridge was dead. Its not outputting any video so that's the next task. The N1700 is fully repaired. Hope the below demonstrates that some but not all machines can be a challenge. Rather than give up just take a break and come back.
Anyway, good luck with your endeavours on your other machines ?
Update June 2020: I won the VCR from e-bay. I'll close this thread and start a new one when I have time to get it up on the bench.