Philips Cassette Heads Problem

[camtechman]

The problem with later Philips cassette recorders ERASE heads has been mentioned before on such models as: N2233, N2234 etc.

To refresh and up date the problem;

The way that they were assembled and the 'potting' compound they used caused the later problem where the thick jelly like compound that held the ferrite bars and the coil in place eventually softens and oozes out of the assembly resulting in, at worst, the ferrite bars to fall out and the goo to migrate to the area around.

But now, several machines later, it reveals a high failure rate of 5/8 and unfortunately I've no found a suitable replacement, although I have been able to recover/rebuild & pot 2 working ones.

Below is the circuit diagram of the relevant part and you will note that its a 3 pin head (centre tapped).

My question is, has anyone come across this problem themselves and know of a suitable replacement. And further more why did they use a 3 contact/ centre tapped device instead of the usual 2 pin type?

[TonyDuell]

I suspect the reason for using the 3-terminal tapped head is that they could then make a Hartley oscillator without needing a separate oscillator coil.

Alternatively "It's Philips". Always a good source of oddites (and before you complain, I happen to be a Philips addict...)

[camtechman]

Tony,

Thanks for the technical info and

"(before you complain, I happen to be a Philips addict)"

. Me too.

[sp10mk11]

AAARRGGGG don't say this just when I thought the great Philips EL/N portables could not trick me anymore you find this, yes never a dull moment with a Philips cassette or a Grundig come to that, decomposing gear wheels, Tony did you manage to get another 485 transport?

Gary

[TonyDuell]

I'm a big enough enthusiast of things Philips that I have 3 of their _minicomputers_ here, along with manuals, etc. And yes, they are at least as odd as some of their tape recorders.

What is the '485 transport' and why was I looking for one?

As for crumbling gears, pulleys, etc, I realised years ago that the only solution to that problem (in all sorts of things) was to be able to make them myself. It's probably overkill for most people, but for the sort of things I work on, a small lathe is essential.

[camtechman]

Hi Gary,

Not yet, I've seen 3 for sale but, despite asking questions about the working condition not one replied, from that I assumed they were duff.

Tony

[camtechman]

What is the '485 transport' and why was I looking for one?

It was meant for me, it gets confusing when there are two Tonys' in the discussion LOL

[camtechman]

TonyDuell,

Both Grundig & Philips cassettes from the same period had crumbling gears, so I assume they both used similar material.

Grundig machines CR409 etc used the "485" transport chassis and Philips N2233 & N2234 etc used their version chassis but their gears turned soft and were prone to the teeth stripping off.

Whether Grundig or Philips from the same period, they both failed and getting replacements is like finding Rocking Horse pooh !

I wish I'd bought a Watch Makers' lathe back in the 70's when it was offered to me but, at the time I was newly married, struggling to pay a mortgage. Ho-Hum.