Philips N4307

[Andrew_Keith]

I have had one of these machines stored away waiting for a rainy day. The problem is the record/playback system switch which is extremely noisy. And despite several attempts at me cleaning it, shows little or no improvement. Firstly i suppose the chances of me getting a replaceament are virtualy zero.
Also due to the extremely fine print on the board i suspect the chances of replacing it without causing much damage are virtualy zero. I suppose as the mechanics and heads are in very good order the only thing i can do is to wait
for one to come up on ebay with mechanical faults and swap boards. Any suggestions would be very welcome.
Thanks.

[reel-to-reel-man]

How have you tried to clean it? is this a physical switch or a slider on a PCB. If you could describe the switching a little more to me I could possibly help, must admit its now one I have worked on much.

[Stewart]

This model uses the sliding type switches where the slider is more like a printed circuit board with contacts linked on it in a seemingly random manor.

The only way to clean the switches is to remove the slider from the main body (which means disconnecting the mechanical linkage) and polish it with something like duraglit. The contact fingers that remain in the switch body are somewhat more of a challenge - the problem being access: You may have to be content with switch cleaner for these, or, fold a long narrow strip of fine wet and dry paper in two and gently feed it through the housing. I would then flush out the housing with a spray to remove any debris from the paper.

If you decide to do this I would suggest marking the slider before removing it so it is clear which way back it goes - get it wrong and the correct contacts won't be made! When replacing it back in the housing feed it in VERY gently and in line with the housing. You may find the mechanical linkage requires slight adjustment afterwards to set the rest and operate positions of the switch: The official Philips method is as crude as you would expect - bend the linkage as required! (There is a specific place to do this on the linkage, but I can't convey this easily).

Just to double your fun there are two switches to attend to in this model!
Looking at the PCB from the component side, with the row of electrolytics accross the bottom right....
S1 (record / PA switch) is the longer switch on the left edge - almost in the centre of the board.
S3 (play / record/ stop) is the shorter switch again on the left hand edge.

Good luck

PS - How come you have one of these where the mechanism is still running? Most of these machines had their rubber parts turn to goo long ago!

Regards,
Stewart

[Andrew_Keith]

Hi Stewart,thanks for your reply,the switch is exactly as you describe. You obviously know the model well !!. I have had the internal P.C.B. strip out twice
and cleaned with duraglit as you suggested, in fact i did both switches as a matter of course.There was an improvement for a short time, but then back to square one. I have come to the conclusion that it is going to have to be a write-off. As for the belts, the machine has had two sets in the last ten years, The present set being in good condition. Even if the switch could be replaced, as you must know the print is so fine and the components so tightly packed together,it would be almost impossible to do without making matters even worse. To add insult to injury the switching sequence is as you say totaly staggered so to bypass in the play position would be a nightmare. I have quite a selection of tapes from the seventies,so this might have been an option, it would just have meant the machine would have been permanently in the play position. I will put it to one side, and if i see one on ebay may buy it. Only trouble is any similar machine will probably be heading for the same switching problems!! Thank you for your hasty reply anyway.

Kind Regards.

[Sideband]

When I worked in the Philips Service department in Waddon (near Croydon) oh.....so many years ago now, I repaired dozens of these and similar machines but of course in those days, switches were readily available. The safest way to remove the switches is a fine-point iron and solder wick. You can get the switches out cleanly but as you say, it is doubtful you will find one now. Most times it was possible to clean the switch using the method described above and then a light application of switch cleaner for lubrication.


Rich.

[Stewart]

Given you've cleaned the switch parts and still have the noise I wonder if the problem is elsewhere? There are quite a number of small electrolytics in the signal paths to and from these switches. Looking at the circuit if these were a bit tired and leaky, d.c. from the supply rails will find its way into the signal paths and hence the switches. Could this make even the cleanest switch seem noisey in operation? Just a thought.

If you're convinced the switch is the culprit, can you slightly re-tension the contact fingers? A gentle pressure inwards with a small probe (with the slider out) on each of the contacts could be worth trying. This assumes that it is the later style of Philips switch where you can see (and get to the outsides of) the contacts along the side. Earlier versions had a plastic moulding along the sides preventing any kind of access.

Regards,
Stewart

[Andrew_Keith]

There is no doubt it is the switch, will try your suggestion, as yes you can get into the sides.

[Andrew_Keith]

Thanks Stewart for all your help, i have found that the noise and intermittency is due to a hairline crack in the pcb, which runs the entire lengh of the record play switch. I am not going to attempt to bridge the tracks, and have written the board off. As the mechanics are in very good order i will look at buying a machine off ebay and swap panels completely. There is one for sale at present that i may bid on.

Regards.

[Booby]

Further to the other answers. To save taking the switch apart just dunk it in a tin of Isopropyl alcohol for a couple of days. If you can find a friendly company making component boards somewhere, they could dunk it (and any of your pcb boards) in their tanks which contain quite hazzardous but effective chemicals like Arklone ... no ground in dirt, grease etc can hide from this.

BTW Maplins do a track repairing epoxy gel... expensive.. but if it saves the board

[Andrew_Keith]

Thanks Booby, but the part of the board which is cracked, is extremely busy with very fine tracks, trying to save it would be more trouble than its worth.
You get a lot of these machines on ebay with perfect electronics, but faulty mechanics, some go very cheap my easiest option is a board swap as my machine has good mechanics,heads and newish belts.
Regards.

[Andrew_Keith]

Hi All,There is good news, i have been offered a replaement board for my N4307. The only problem is that it is from an N4308!! The way that i see it there are three issues here. The 4307 has a two watt amp and is fed from an overwind on the motor.The 4308 has a 4 watt amp and has a separate mains tx presumably because of the extra power required. The 4308 has an additional control for line and mic mixing the 4307 does not. And last the 4308 has a leaf switch operated by the speed change switch, which presumably changes the bias for the two speeds. I think i can overcome all this in the following ways. I can fit a separate mains transformer to cope with the extra current required by the amp as the 4308 has AD161/2 output transistors. It will mean drilling the chassis, but there is plenty of room. Second i can saw off the spindle from the mic/line pot (it is plastic) so wont have to drill the top facia just leave it in the line position. And last set the bias switch permanently in the 3 and 3 quarter speed position. Before i pay the £25 pounds for the board any views??.

[reelguy]

Hello Andrew. It's only my personal opinion, But it seems an awful lot of time and expense to try to repair a machine which can be picked up for about £5 or so at a boot sale. I have a 4307 which has suffered from dissolving belts. Quite common with many Philips recorders from about 1966 ish. Earlier ones seem OK. If any of the parts are of use to you let me know. Free. I'll only expect you to pay postage.. Let me know if you're interested . Reelguy PS. £25 for a board. I would expect to get a couple of M/cs for that

[Stewart]

I too think the cost is on the high side - I'd expect a complete machine for less than that! Whilst I've seen some go on e-bay for £40 or so, others struggle for a bid...

Whilst quite possible to convert this board to fit in you machine I think the time could be better spent trying to bridge the breaks in the original pcb. I know the print is fine and not too well adhered to it, but it must be worth a try?

If you go ahead with the conversion and need any info on the differences let me know and I'l look them up - although it sounds as if you are clued up on this already!

Either way, good luck,
Stewart

[Andrew_Keith]

Thanks Reelguy and Stewart, i have i must say never been lucky enough to see one of these at a car boot, I am going to sit and think about this for a while now, think i may have been a bit hasty, but not parted with any money yet. The machine i have has fairly new belts hence the temptation.

[Andrew_Keith]

Hi Chaps, Just an update on my previous post. I have been told that if i fork out the twenty five quid for a replaceament board there will be no guarentee with it, and it will be sold as seen. I have decided not to go ahead and will keep an eye out on Ebay. Trouble is as Stewart quite rightly says they seem to either attract a lot of bids or none at all. What i will look out for is one on buy it now. As i always seem to miss out at the end of bidding!.

[reelguy]

Hello Andrew. I must confess to being a little puzzled that you have a 4307 but are looking for a 4308 replacement board. ? As I mentioned in my previous post I have a 4307 which I can dismantle and remove the board or any other parts if required. these will be "FREE" . Only cost to you would be the postage, Which for a board should'nt be much. If you lived locally to me you could even pop round and pick it up. {Whole M/c for that matter} Then it would be for Nowt . Regards Reelguy..

[Andrew_Keith]

Thanks Reelguy, Wasnt looking for a board from an N4308 was offered one. As for your offer on the N4307 i am staying at a friends in Birmingham for the week, will contact you when i return to Manchester at the weekend. And thank you for your kind offer.

Regards.

[Andrew_Keith]

Reelguy you have a pm

[reelguy]

OK Andrew. Let me know when you get back from your trip. I tried the 4307 out that I have and had to pull tape through in play position [ no belts] but the sound was Ok. I didn't try record. Please note however that the remains of the old belts are still there ready to get on your fingers . Horrible stuff. Best to remove as much as you can with a small piece of wood and clean off remainder with surgical spirit {from the chemist} regards Reelguy