1974 Philips N1500: Chassis No2: Episode 1, making a start
Well finally the set of belts for the second N1500 bare bones chassis have arrived. This has taken over three weeks to resolve as the first set from Germany disappeared into the great postal void, never to be seen again. A second set were ordered but this time from Hungary and they turned up today, finally I'm able to set about seeing how this other N1500 chassis behaves.
As mentioned before it looks to be in remarkable, original condition despite the cabinet having to be dumped due to woodworm. Obviously the belts on this like the other deck had tuned to goo depositing themselves all over the eddy current discs. This required the usual messy cleanup but 'CIF' really is your friend in this matter. I also needed to sort out some power as the original lead with special plug was missing so a modification was in order.
Depending on how this chassis turns out, will determine how the first player is finished or not. The following Vrat-Tube video below details the two projects and covers the start of this second chassis.
The video was shot using my new HD JVC camcorder and with a shotgun/boom mike for better audio. I've also started using a very complex video editing suite called DaVinci Resolve and had a play with new titling.
I've also greatly shortened the length of the intro and outro set pieces for the channel branding. I hope this meets with the approval of those that were unhappy with the original intro/outro length and sound level. Most of all I hope you enjoy and if you're not already subscribed, please consider doing so.
Episode 1; Making A Start
Coming soon Episode 2; What happens when power is applied
As a teaser, power was applied and as as ever with me I'm presented with a rather fun fault to chase down. The unit was powered up without a tape loaded, the head rolled into position as if lacing perfectly, however it won't unload or stop, it spins forever. The 30 second no action protection circuit is not operating. As I say this fault and the hunt for the cause will form episode 2.
As there appears to be little interest in this or indeed any activity on the forum of late, I'm considering ceasing duplicating updates here and just publishing project updates directly to the youtube channel. The first video above in the recent series over there seems to have been my most popular thus far, gaining many times more views than previous uploads. They certainly aren't all from Vrat as there's less than 5 active members nowadays.
The next instalment, episode 2 is now online for those interested. Anyway to be notified on further uploads on this project or any other new projects, you will need to click the bell icon.
Looking good Chris. I don't think it's lack of interest, I think it's life getting in the way....I was out most of yesterday, a surprise birthday party to attend in the evening and....the wife's birthday today so I doubt I'll be around much either. Glad you got the protection circuit working and in the end such a simple solution. Await the next phase eagerly!
Plenty of interest here Chris, I was waiting for the next instalment
I'm also finding these old VCR's interesting too, I've only ever experienced VHS really, not counting camcorder formats such as Video 8 and Mini DV, so I'm finding it really interesting to see what these other formats were like. Your Youtube video's are great too, getting to see the machines in action!
Sorry I can't add much of anything useful, other than keep up the good work 🙂
PS: I'm back at the bench playing with that Motorola TV again!
Very short update & supplement to episode two.
- Tested E-E and its not working, as of yet, no idea why.
- Lace up, working though a little sluggish, I believe this due to hardened grease.
- No Video playbacj just sound. turned out broken or snipped wire on back of modulator
- Video Playback, kind of working but cannot track the disturbance, is it tape or is it machine?
- Audio playback good, this makes me think the above video fault is the machine.
Although this machine appears to be in better condition than the first, it does seem to have a fair few faults present.
I can't really progress any further until I have some known good N1500 tapes. Some tapes should be arriving towards the end of this coming week. I've cleaned the heads but its not them, I'm left wondering if the input and exit guides might need adjusting. I will see if there is a procedure to follow with regards to scoping the RF waveform whilst adjusting the guides. This is where I really do need the service manual as I'm struggling with the scraps I have. As mentioned to another member in a private message, I was outbid this week on a nice original Philips N1500 manual in binder and with all supplements, I thought I had bid enough at £120 to secure it but it went for £122 !!!! ? I thought I was mad but there's another mad hatter out there.
I am not quite sure going about scoping the off tape FM on these machines as we would normally do it, ie. triggering the scope from the SW25 test point (drum FF see below) to lock the FM waveform on the scope.
The N1500 did not use a drum Phase Generator (PG) Flip-Flop (SW25 signal) as there is no head switching (as per VHS/Beta) as such on this format, the heads simply being wired in series via a single rotary transformer, the head servo does use a pickup head and a magnet though, maybe a look at the English version of the N1700 manual might yield some clues, as they too just wired the heads in series and the tape path/guides etc. are substantially the same.
After sorting out the broken/snipped wire, I've now got E-E partially working and the signal indicator (lA2) now illuminates.
The TV is tuned in to channel 1 receiving test card F and test card, both card and music crystal clear.
Now, when I tried tuning CH 1 & 6 on the VCR's to the test signals, I can only tune the test card as a very dark picture and no test card music can be heard just loud buzzing. A further fault must exist and will now give me something to do until those tapes arrive. Expect episode 3 to be cover the sound and vision fault on E-E.
The head drum loading on this deck has been gradually getting worse, (read weaker) and has not been fully loading, needing a helping hand to lock into position. Hoping its not M3 failing but more to do with old grease or the lacing failing, therefore there was nothing for it but to remove the dreaded lacing cord assembly and investigate why this is happening.
Those of you who have followed my N1500 threads and countless others web reports elsewhere, will be all too familiar with the N1500 Achilles heel, namely the lacing of the drum head assembly. Even back in the day when they were new it was a problem and as such, the subsequent N1700 doing away with cord lacing entirely. The loading motor exerts much force with repeated head drum operations, coupled with that the lacing cord can break as can the plastic cog and cord reel. Let alone 45+ years later age related wear and degradation of plastic.
Removing it no matter how daunting would allow me to check for wear, clean and lubricate where necessary. The cord on this deck is the later version, the one which passes through the chassis and terminates on the underside to a couple of springs. To gain access for removal, its necessary to remove the DIN video/audio back plate and the voltage selector wheel.
Next the two ends of the drum springs have to be released from their captive hooks on the drum base, followed by releasing the two nylon guides from the springs under chassis. All that remains then is to undo the grub screw on the cord wheel and slip it over the M3 motor cog. Sounds easy but when its your first time you need plenty of photos and patience so as to not have the whole thing unravel as I need to know how it goes back.
The cord and springs all seemed to be taught, very little wear and in overall good condition. However all was not well with the cord containment wheel. This had clearly aged from a bright white to an off yellow and had split in half near the top where it grips the M3 cog, this could in all likelihood be the cause of the final load not positively locking, slipping?
Next was the removal of the lower drum so as to be able to clean and re-lubricate
Well that was the first time I've had to change the drum lacing on a N1500, the task has been completed. Thankfully it worked first time and happy to report the drum/head lacing stall has been cured, it now loads smoothly and quickly without hesitation