Philips 4307 and 4308

[Gavtech]

Thread split from original thread. Previous postings can be found here.

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Jon, your friendly neighbourhood moderator
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Originally Posted by Andrew_Keith

P.S does anyone know the voltage of the small wire ended bulb that lights up the VU meter. I have lent out my AVO and want to try and get a new lamp from maplins or the like. I guess it is either 6 or 12 volts? It is fed via a resistor from the secondary of the motor/transformer.

Hi Andrew
I can't tell you the actual rating of the bulb.... but when working 4.98 V.AC is dropped across it...
ie a Nominal 5 Volts.

The best match I can find at Maplin is a 6 Volt wire ended / Low current bulb specifically designed for backlighting.
See 6V Wire Ended Bulb at Maplins

Good Luck

Gavin

[Andrew_Keith]

Thanks for that, The other day i went to maplins and bought a 12volt wire ended bulb thinking it was the most likely. I fitted it the night before last and although obviously dimmer than it should be, it is still quite adequate as it is as you know housed in a little mirror enclosure which reflects it onto the VU meter. Anyway i will leave it in as under running a bulb can only serve to increase its lifespan

Kind Regards

[Andrew_Keith]

Gavin, if its not a silly question how can you open up a 4307 without removing the top plate first

Unless you took out the screws from the bottom of the case, turned it upside down and the whole lot fell out

[Andrew_Keith]

If you require a new main belt, then Colin Braddock tape recorder centre mentioned earlier in the thread sells the complete set of belts for the 4307/4308 for £18.50 and will post them out to you within 24 hours. A bit dear i know but if you only want the main one, i am sure it should be a fare amount less. He is based in Blackpool.

His number is 01253 345049.

[Andrew_Keith]

Just a tip Gavin if you are working on your 4307, when i was repairing mine i found that the leads to the internal speaker were annoyingly short, making it hard to lift out the chassis to any great degree without unsoldering each time, or risk the chance of straining the tagstrip on the speaker. So i used a couple of cores of light gauge cable, and extended the original cable by about ten inches and insulated the soldered join with heatshrink sleeving. It then allows the chassis to be removed to a comfortable degree to work on without having to unsolder the speaker each time Just make sure that when you replace the main chassis into the case, that you tuck the cable out of the way of the flywheel and underside belts etc. A simple tip i know but it makes life alot easier

[Andrew_Keith]

Hi Gavin, You say you have only done the bottom of the machine so far and are fairly clean I think you will find its a different matter when you start on the top Make sure you are wearing old clothes when you start

Good luck

[Andrew_Keith]

If any reel to reel fans are interested, there is a site on the internet called John's Radio Web , which gives detailed internal photos of the N series of reel to reels. Its all in german But the photos are worth a look through

[Gavtech]

Originally Posted by Andrew_Keith

If any reel to reel fans are interested, there is a site on the internet called Johns Radio Web, which gives detailed internal photos of the N series of reel to reels. Its all in german But the photos are worth a look through

Thanks Andrew for the direction to this site. Very interesting. One remark regarding the 4308... I note that it gives the Product Period as being from 1968 until 1975, which by today's standards is an amazing length of time for a product. [ Unless all that is referring too is the standard 7 year period that Philips 'supported' the machine with spares etc. ]

The pictures also showed me a point where i had gone wrong. No doubt your 4307 belts were in a similar condition to mine ... Just mush lying in the machine... so i had to deduce the belt paths ... Not that difficult. But I discovered via the picture that the tape counter belt is crossed which I had not realised... No doubt i would have discovered my error when reassembling the machine and the counter went backwards!
I note also that the main flywheel / motor pulley belt appears to be white ! .. albeit the picture is a little fuzzy here.

After your last posting about the mess i might expect cleaning up the top deck ... I felt a challenge ... and immediately went to do it... I was in smug mode because all was cleaning up easily and well without any mess ... until I reached the belt which had degenerated around the clutch pulley... and seems to have almost amalgamated with it.
Using the chewing gum remover worked very well indeed , particularly on the metal pulleys and metal parts... cleaning them to sparkling in seconds.
The clutch pulley has proved much more difficult and turned a ten minute job into one of many days , as i go back to it periodically as you did .

I have tried increasingly strong solvents not to a great deal of effect ... I dare not try anything stronger or I will be dissolving the plastic!
However it is coming off slowly - with a bit of elbow grease and patience.
It's a fine line before one gets to the "This is daft'" moment.

[Andrew_Keith]

Hello Gavin, I must admit i wondered how you were getting along. As for the clutch assembly, i gave up trying to clean it in-situ. And removed it completely (there is a circlip under deck). And soaked it in a bowl of hot water and kitchen de-greaser, then using a toothbrush removed the gunge which came away a treat . However i found that the clutch had turned to gunge along with the belts. Here i got stumped Clutch parts are no longer available, not even from Colin Braddock. I gave it much thought and decided on looking in my toolbox, decided to try using a flat hard rubber washer, the kind that is used to seal a sink outlet. This i sandwiched between the two plates of the clutch, on re-assembling it would appear to work a treat. It slips at the right amount of torque, but drives ok on take-up. And lets face it as long as they are making plughole seals for sinks, spares are readily available . As for the counter i made the same mistake putting it on the right way!!. Then realised it was going backwards. However in the figure of eight the two sides of the belt tend to rub against each other . Which seems a bit of poor design to me. Mind you i think that all the belts in the machine are typical cassette deck type available over the counter, except for the biggy!. I would be interested to hear what you think about the sound quality of the machine when you have finished. As i find it VERY disappointing, as i mentioned in a previous post the poor quality is down to the amp and the speaker, as i tried it with line-in from an impeccable source, so cant blame heads or tape here I may decide to use it as a deck only most of the time, using line in/out into my main hi-fi system. I think using it stand-alone will be for novelty purposes only. I know the next model up (N4308) uses bigger output transistors(AD161/2) as opposed to the (AC187/88) used in the 4307, also it has a separate mains transformer, so expect this machine to sound somewhat better. Also the frequency response of the 4307 is quoted as 60 to 14000 cs which is pretty poor by todays standards.When i get around to picking up my pre-recorded tapes from Leeds i WILL use the machine if not very often.

Hope all goes well for you.

Forgot to mention that the production run was VERY long, i think it was the most popular reel to reel Philips ever made. They used to also use them in schools and colleges. The retail price of the N4308 in 1975 was £95 which must have been a fortune at that time

[Andrew_Keith]

Just an afterthought, does anyone know why Philips used two types of transistor. Silicon in the pre-amp stages, and Germanium in the driver/output stages. As silicon were obviously available why not use throughout

[Stewart]

Another alternative repair to the take up clutch that has worked well for me is to cut two 1/2 inck grommets in half and position the four pieces inside the assembly. The grooves in the grommets fit quite nicely on the moulded flanges inside and, as it seems with Andrews' sink gasket, the take up tension was just right.

The chewing gum remover tip is useful but I'm sure the swarfega method works out cheaper (see earlier post) - I recently cleaned out a clutch assembly full of gunge using this - in a couple of minutes it was back in the deck looking like new.

I think the biggest problem with regard to sound quality is the plastic cabinet. With an external speaker connected they sound reasonable - although a long way away from the top quality decks of the day. I should also add I've only had experience with the 4308 amplifier though - but I can't see why the 4307 should sound any worse - just not quite so "powerfull".

I wouldn't have thought this machine their best selling reel to reel: I would have given that honour to the EL3541 some years earlier. By the time of the N4307/8 it was competing with their own cassette system and wider use of stereo recorders? Either way,they both have their share of belt troubles! (just to bring it back on topic a bit!)

Stewart

[Andrew_Keith]

Hi Stewart, The main problem with the 4307 is probably that it breaks into distortion at fairly modest power, as well as the plastic cabinet resonating. However the 4308 that you have has a 4watt output compared to the 2watts of my machine. I have many years ago heard the two machines side by side and there is a difference. Mainly as i say with distortion levels.

Regards

I may well be wrong about the popularity of the machine, but it did enjoy a very long production run. I remember seeing them in what was then Vallances still being sold in 1975. Given that- according to records they first came out in 1968, that has to be a success story for the model Other wise why not withdraw it earlier?

[Andrew_Keith]

Anyway, as you say drifting off topic so i will leave it there

[DOFFERY]

Further to the problems of the well known 4307/8, re. the clutch inserts, I must admire your many solutions, however if I may I would like to offer my solution, which I do on a day to day basis. An old flat belt of a thickness to fit into the grooves on the clutch plate, cut to overhang the periphery by about 1.5mm & also cut out to allow for the extra thickness of the clutch plate at the edge. It should be no higher than the central boss (to allow upper/lower plates to move easily). Also note that the LH(feed disc) has the inserts mentioned ,placed in the grooves to the right of the strip(looking down on the clutch plate) the right hand disc has the insert on the left hand side.When completed & lower/upper plates positioned together & turned by hand you will feel the smoothness in one direction, the braking in the opposite .Hence the braking will be improved, assuming all other adjustments being correct.

The 4307/8 plus the earlier versions o2/3/4 etc. upon which the 4307/8 was based was indeed one of the most popular & best sold of all Philips machines, in 71 being £61. 50 only.

Hope this helps a little.

Colin



The lamp by the way is 6V 45ma

[Andrew_Keith]

Thanks for that Colin, as my machine is working ok, will leave as it is. But i will make a mental note of your solution for future reference. By the way i bought a wire ended bulb from Maplins (12volt) thinking it was twelve volts. Having fitted it- it is of course dimmer than should be, but in fairly low lighting levels is more than adequate. So will leave it in, as under running it can only serve to preserve its life

Kind Regards.

[Andrew_Keith]

Stewart you have a PM.

[Andrew_Keith]

Found this today Thought i would post it incase anyone out there is interested.http://cgi.ebay.co.uk/ws/eBayISAPI.d...778639690&rd=1.

Hope i have posted the link o.k

[Andrew_Keith]

Hello All, Need some opinions or further advice on my 4307. Having recieved some tapes kindness of Stewart on our forum i have found a new problem Every now and then when pressing the stop key the drive belt that turns the take-up clutch jumps out of its groove. I think there maybe too much take-up torque, am thinking about getting a thicker belt to compensate for this, as i dont fancy taking the clutch apart again, any advice appreciated

[Stewart]

Hmm, not had problems with the take up reel belt. I would imagine that this is a replacement belt - I wonder if the diameter / profile needs a slight tweak? Do you have an alternative salvaged from old cassette recorders that you can try? At least this is one of the easier belts to source an alternative for.

The only other thought is the take up clutch binding. Given that this is non original maybe it to needs a little "adjustment". The sink washer is a neat idea for replacing the original rubber pieces but it maybe a few shim washers are required on the main shaft between the spool and clutch plates to lower the torque a little? This is typically what Philips used to set reel height and torque so wouldn't be out of place at all!

My 4308 is near the bench at present so if it would be helpful to assess torque or belt sizes etc on mine let me know.

Mine has decided to throw off its flywheel drive belt every now and then if I dare to change speed so I too am looking to find an alternative belt. The one on it clearly doesn't like being stretched so much by the radial arm that lifts it off the shaft during speed change. (Anyone familiar with fitting a hose and tools to a 60's Hoover Junior 1334 will have an understanding of how this mechanism works!)

Glad to see you back on the forum Andrew.

Stewart

[Andrew_Keith]

Cheers Stewart, I dont think the clutch is binding, It certainly seems to run smoothly. But the take-up belt does seem a little flimsy though. As when the machine is in stop mode, the take-up belt seems to want to try and "climb" off the pulley. I think if this belt was the same diameter as the flywheel belt underneath it may solve the problem. The belt just seems a bit too thin, more like the tape-counter belt. ( no i havnt got them mixed up) . Think for the time being i will let the clutch rubber bed in as it may settle down. The problem only happens about once in a week of use so its obviously borderline . Let you know how i get on though. The reels of tape you sent me perform very well. And recording from vinyl from the record out socket on my hi-fi amp the results are quite pleasing.

Glad to be back