Filmosound 179

[Roger Trimshaw]

Hi everyone,

I'm hoping someone knowledgeable with the Bell & Howell Filmosound projectors can help me. I recently purchased a Filmosound 179 Model CB with original speaker. I've been told it works but I'd like to give it a good once over before powering it up. I wanted to get a service manual with the amplifier schematic for it but the only one I can find says it's for a 179 Model A.

Does anybody know if the the variations of Model (e.g. Model A, B, C etc) had the same amplifier circuit?

Thank you

[Maurice Leakey]

.....Does anybody know if the the variations of Model (e.g. Model A, B, C etc) had the same amplifier circuit?....

Roger

You may be interested in the attached schedule of Bell & Howell 16mm sound projectors. There are some model 179 variants, but not yours.
Bell and Howell 16mm Projector Models (paulivester.com)

However, the 179 heading has the words:-
Popular optical sound model, many different amplifier designs.

This seems to answer your above question.

[Neil Scully]

Hello Roger,

With a valve amplifier of this age it is vital to replace all the wax paper capacitors and electrolytic capacitors. even if it "works". There is a high likelihood that one will fail, the bad news is that this will potentially take out either the power transformer or the output transformer, both would be next to impossible to find replacements for. As Maurice says there are quite a lot of variants. If you have a look over on 16mmfilmtalk.com you will find several current threads on B&H amplifiers with lots you will find relevant. You will also probably find Ken Layton can provide the required schematic.
Unfortunately the B&H amplifiers are some of the hardest to work on physically. I have been doing amps for over 40 years and it took me days doing my 202 amp where a Fender or Vox guitar amp would take me an afternoon.

[Maurice Leakey]

....As Maurice says there are quite a lot of variants. If you have a look over on 16mmfilmtalk.com you will find several current threads on B&H amplifiers with lots you will find relevant. You will also probably find Ken Layton can provide the required schematic....

Roger
You may have to join to read the Forum.
16mmFilmtalk.com - Frequently Asked Questions

[Lee Mannering]

Such beautiful engineering! My first 16mm sound projector was a Ampro Special Stylist another nice piece of engineering.
Dad was always a Bell & Howell man.

[Roger Trimshaw]

Roger

You may be interested in the attached schedule of Bell & Howell 16mm sound projectors. There are some model 179 variants, but not yours.
Bell and Howell 16mm Projector Models (paulivester.com)

However, the 179 heading has the words:-
Popular optical sound model, many different amplifier designs.

This seems to answer your above question.

Thank you for your reply Maurice, it looks like you're right that they made different amplifier versions. Seems strange that they kept changing the design. And I did put in a request over at 16mmFilmtalk to see if anyone there has a schematic.

[Roger Trimshaw]

Hello Roger,

With a valve amplifier of this age it is vital to replace all the wax paper capacitors and electrolytic capacitors. even if it "works". There is a high likelihood that one will fail, the bad news is that this will potentially take out either the power transformer or the output transformer, both would be next to impossible to find replacements for. As Maurice says there are quite a lot of variants. If you have a look over on 16mmfilmtalk.com you will find several current threads on B&H amplifiers with lots you will find relevant. You will also probably find Ken Layton can provide the required schematic.
Unfortunately the B&H amplifiers are some of the hardest to work on physically. I have been doing amps for over 40 years and it took me days doing my 202 amp where a Fender or Vox guitar amp would take me an afternoon.

I am going to replacing all the wax/oil and electrolytic caps, Ive read too many horror stories of bad caps destroying amps. Thank you for referring me to 16mmfilm talk. Im hoping someone has the schematic for it, would be nice to have as a reference just in case the amp does not work.

Also, it looks like the amp has those mica "domino" caps, Ive read just to leave them be but have also read to replace them. They all seem to be in good shape, no cracking or splits. Would you recommend to leave them be?

[Neil Scully]

Also, it looks like the amp has those mica "domino" caps, Ive read just to leave them be but have also read to replace them. They all seem to be in good shape, no cracking or splits. Would you recommend to leave them be?

Once you get a look at the treads running over on 16mmfilmtalk you will see that you have to be careful with the dominoes. The larger values are not mica but instead are wax paper, so advisable to change. the other reported issue with some of these is microphonics, this can be detected by tapping them whilst the amp is on.

[Maurice Leakey]

Roger

You may be interested to know that Oldtimer Cameras, here in the UK, can supply a printed Repair Manual for the 179, as it also includes the models 185, 285 and 385, it might have some information that could help you.

Scroll down for the Repair Manual. It's priced at GB pounds £9.95, plus postage.

Bell and Howell 179 Printed Manual (camera-manual.com)

[Neil Scully]

I can thoroughly recommend the OTC manuals, I have bought them for my 202, 646 and 2592. Excellent value at £9.99. In comparison I just had to pay $95 for a manual reprint for a milling machine we just bought.

[Roger Trimshaw]

Neil Scully - I'm desperately hoping its not molded paper caps haha there are so many packed in beneath a whole lot of wires to get to them.

Maurice Leaky - Thank you for referring me to OTC, I sent them an email to see what models they have schematics for. The one thing that is throwing me off is the year of the manual, on OTC it shows 1955 but it seems that the 179 was made until the late 40s.

[Maurice Leakey]

Roger Trimshaw [/QUOTE].....Thank you for referring me to OTC, I sent them an email to see what models they have schematics for. The one thing that is throwing me off is the year of the manual, on OTC it shows 1955 but it seems that the 179 was made until the late 40s....[/QUOTE]

Roger
I agree, but the manual also covers the later variants:-
179 up to 1949
185 1949-1951
285 1955
385 1955-1961

[Roger Trimshaw]

Ah ok that makes sense. OTC did get back to me in regards to the wiring schematics, they said the manual has 3 schematics for the 179, but does not state what the schematics are for. I suppose I could take a gamble and order it to see if the schematic looks correct.

[Maurice Leakey]

Roger
It's a good idea to get the repair manual. It may contain other useful comments.
Don't forget to order the Repair Manual, not the Instruction Manual mentioned above it.

[Roger Trimshaw]

Well the manual finally arrived, great reprint, nice quality. Unfortunately it does not contain any amplifier wiring schematics only schematics for the projector motor. However, I was able to find a legible copy of the amplifier schematic online for the AB model. Seems that most models were fairly similar, so I'll be going through the amp soon to compare.