Philips N4308 Reel to Reel Check Out

[DMcMahon]

Late 1960s/early 1970s 4 track, 2 speed, mono solid state reel to reel recorder.

Nice looking recorder in quite good external condition for its age.

It was sold as "not working", there is a label on the top panel saying Play and Fast Forward fast wind do not work, also says recording quality is poor.
Seller said Play and Fast Forward wind do appear to work.

Replaced thin 2 core mains cable with 3 core and earthed the chassis metalwork (which connects to electronics ground).

Opened it up expecting to find drive belts missing or turned to goo, pleasantly surprised to find all 4 belts intact and appear good condition.

Even though all tape transport piano keys press down and engage they are somewhat stiff and the associated levers are somewhat gummed up, so will strip, clean and relubricate as required.

One of the worst gummed up levers was item 302 (not listed in spares listing, there is no full parts listing). This lever is on the underside and has leaf spring item 128 pressing up against it. There are 2 small (2.4mm) steel balls (items 127) under item 302.

After removing, cleaning and relubricating the parts in above paragraph, refitted the parts. Then removed the top of the Supply spool table to see what is necessary to remove the various other gummed up levers, it looked quite a strip down so thought would come back to it later.

Then found a steel ball rolling around on the top plate the same size as the 2 balls referenced above. Could not see where it might belong, looking at drawing and parts list there are 2 other pairs of steel balls, items 104 under leaf spring 105 (these are larger at 3/16") and items 150 (same part number as balls 127) under Z bracket item 116. So assume at the moment that the found steel ball is one of the item 150 and it has escaped from under the Z bracket, will find out later when the bracket is removed.

Powered up and played a tape, sound is reasonably loud but very intermittent, fast wind in both directions works reasonably well. Play struggles at times with the tape not always being taken up by the Take Up spool.

Removed the Supply turntable parts to start stripping down the various levers. Found that the 4 black rubber brakes (items 55) are in a poor condition, seems to be a lot of gooey rubber in the Friction Wheel item 56, seems to be quite a large quantity for the small sized brakes that are turning to goo. Has anybody got a photo of the brakes in good condition, saw reference somewhere to brakes being repaired using strips of O-ring/drive belt, has any body got a photo showing this type of repair ?

Edit update - I now think that the referenced brake repair using O-ring was actually for the clutch.

David

[DMcMahon]

Items 55 are called "Brake Shoe" in the N4308 parts listing (Brake Block in N4307 parts listing & Friction Block is similar Pye 9123 listing), from older Threads they are components of the turntable clutch.

David

[DMcMahon]

Post 3 of the linked Thread shows item 55 at Post 3 (photo shown shows the same part used as turntable brake). Post 2 of the Thread shows small O-rings being used to replace item 55.

Other Posts in other Threads reference using cut lengths of drive belt and also just gluing the 2 halves of the turntable clutch together.

https://www.google.com/url?client=in...a9f8yThgMIoyKi

David

[ben]

The rubber clutch inserts take some trial and error to get right, particularly on the supply spool. Too much rubber and they produce drag and hence wow in the sound - check while it is playing by unwinding some tape and see if there's a change in speed. Too little and you will have spillage from fast wind to stop and worse tape-head contact.

Likewise, in the take up spool, too much rubber here will lead to very sluggish rewinding. with the drag.

[Vicboduk]

If you scroll down to post#11 in the link provided you can see that the reel clutch rubbers can be replaced with a piece of flat belt. It’s important that the end of the rubber over hangs the wheel rim by approximately 1.5-2.0mm.
This thread, posts 3# , shows the original and my solution where I cut new rubbers from a piece of 2.0mm thick rubber mat.

[DMcMahon]

Do not have any suitable rubber sheet to hand and my square section drive belts are very small diameter so probably would be too flimsy, so will try some small complete O-rings to see how they perform.

David