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Other Vintage Household Electrical or Electromechanical Items For discussions about other vintage (over 25 years old) electrical and electromechanical household items. See the sticky thread for details.

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Old 16th Mar 2019, 2:29 pm   #21
AC/HL
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Default Re: Ampro Stylist projector

I think we got off on the wrong foot here. The opening post unfortunately conveyed the impression that AmproStylist had much less experience than he actually has. We can only take that at face value, as we do get a lot of new members that do need safety advice and we'd be negligent if we didn't realise this.
However, AmproStylist just needs the correct schematic in order to solve his dilemma, and so far it seems to be elusive. The one linked to doesn't really help unfortunately.
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Old 16th Mar 2019, 3:08 pm   #22
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Default Re: Ampro Stylist projector

I have not yet seen a snap shot of a mains dropper section in this thread however I can fix that.
The mains takes two paths that split between the heater chain and the supply to the HT rectifier.
The projector has discreet resistors in series however a good idea can be had from the diagram of a small radio with the resistors in one single unit that is taped off.
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Old 16th Mar 2019, 9:24 pm   #23
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Default Re: Ampro Stylist projector

Found it and finally managed to get it to upload!
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Old 16th Mar 2019, 9:45 pm   #24
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Default Re: Ampro Stylist projector

Thank you for uploading this- it's rather heart-warming to see such a nice example of the earlier form of component symbols in use
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Old 16th Mar 2019, 10:59 pm   #25
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Quote:
Originally Posted by wd40addict View Post
Found it and finally managed to get it to upload!
Wow!
that's amazing quality. Thank you very very much.

Where do you find this stuff?

With this I can wire and fire it up. I'm a happy camper. Will post pics when done.
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Old 16th Mar 2019, 11:52 pm   #26
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Default Re: Ampro Stylist projector

Only just spotted this thread!

Can I ask the OP what the state of the actual Stylist Projector is, please?

These are a lovely looking projector and can work very well. I have two, one an 'antique gold' kind of colour and the other silver. I've spent some time in making the former work to a good standard (both picture and sound) and it is one of my favourites. Both the models that I have are this 'educational' variety without a separate transformer. They are compact, reliable and quite decent for what they are. The amplifier is nothing to write home about, but it does the job and with a decent photocell, sounds quite reasonable. I actually traced the circuit of the amplifier out a while ago, so it's great to see an 'official copy'!

I wonder how many more of these projectors are still 'out there'?

Best regards,

Paul M
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Old 17th Mar 2019, 2:13 am   #27
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Default Re: Ampro Stylist projector

Quote:
Originally Posted by wd40addict View Post
Found it and finally managed to get it to upload!
Quote:
Originally Posted by Herald1360 View Post
So.... back to the original question, does anyone know whether a schematic can be found to help put the amp back together?

The audio side will be relatively standard but the exact power supply configuration could be "odd". At a guess, the ac feed to the rectifier will be taken off the resistor dropper chain at the 205V tap probably via a series resistor and there will be further resistors from there in series with the heater chain to limit the heater chain current to 150mA. Another possibility is that the rectifier feed comes direct from mains- this would explain the "6-8W" output claim.
Brilliant!

Well done that man.

Also chuffed to see my guesses about the supply side weren't far off
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Old 17th Mar 2019, 9:12 am   #28
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Default Re: Ampro Stylist projector

New Educational here. Belonged to a late friend of mine, also called Paul, and I like to use it occasionally as a kind of memorial.

As PaulM says they actually work pretty well. Biggest problem with mine has been sourcing a drive belt, not helped by Ampro using two different sizes. Modern one's aren't made of rubber and do not have much give. The 'correct' size was just too tight, so ended up using the larger size and dropping the motor.

Selenium rectifiers were weak and bypassed with silicon diode and resistor chosen to restore HT voltage to correct level.

Regards,

Yet another Paul!
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Old 17th Mar 2019, 10:03 am   #29
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Default Re: Ampro Stylist projector

Yes indeed, Paul, the drive belt is a weird size. I didn't know that there's two types. I managed to find one that works in my 'assorted belts' boxes. Heaven knows what it was off.

Also bypassed the rectifier with modern. You have to be pragmatic.

Picture attached of my 'antique gold' one on a very rugged 3 leg period projector stand.

Best regards,

Paul M
www.becg.org.uk
www.projectvivat.co.uk
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Old 17th Mar 2019, 12:02 pm   #30
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Default Re: Ampro Stylist projector

Mine is a silvery color.
It is (was) in good working condition I think. It could spin at least some things, not sure if all parts moved correctly.

I had no film to test it and I bought it for the purpose of guitar amplification.

I'll take some pictures of the parts that I don't need. A cup of coffee and shipping costs and I'll be willing to ship them to someone who can use them.

What are the benefits to bypassing the selenium rectifier and using diodes instead?

P.S.
They really are beautiful to look at.
Much pretty than old Bell & Howells
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Old 17th Mar 2019, 2:03 pm   #31
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Default Re: Ampro Stylist projector

Selenium rectifiers often weaken with age leading to sagging HT. They can also fail with a foul smelling cloud of smoke.

You cannot bypass with just a diode. There has to be a resistor in series with the diode to mimic the losses in the old rectifiers and keep the HT at the same level.
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Old 17th Mar 2019, 4:06 pm   #32
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Default Re: Ampro Stylist projector

Sagging voltage might actually be desirable for guitar. But if I decide to do diode resistor, do you have any recommendations of components?
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Old 17th Mar 2019, 4:18 pm   #33
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Default Re: Ampro Stylist projector

Diode the ever popular IN4007, try 220R as a starting point for series resistor and move up or down in value as necessary. I didn't completely bypass my selenium but 'topped it up' with the diode/resistor.

Resistor will need to be a decent wirewound and it will get pretty hot.
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Old 17th Mar 2019, 4:34 pm   #34
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Default Re: Ampro Stylist projector

Thank you.

Since I gutted the projector I actually have one of those big green resistors I could use. It is 250R, a bit on the high end though.
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Old 18th Mar 2019, 5:28 pm   #35
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Default Re: Ampro Stylist projector

Now that the proper schematic is furnished, things look a bit more promising!
I looks like they're pushing the 35L6's to the maximum, 216 on the anodes and 110 on the screens, so it's good for about 6 watts. I never seen a 6BR7 valve used here!
I would be tempted to eliminate the 50C5 tube and eliminate the high wattage heater dropper resistor and use a cap dropper. Of course the heater drop has to be recalculated because of 50 volts less in the heater chain. Also, increase the size of the smoothing and storage capacitors to at least 50mfd because of the 50CY mains.
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Old 19th Mar 2019, 9:01 am   #36
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I'm still too much a beginner to really understand what all these changes would do for the sound?
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Old 19th Mar 2019, 9:57 am   #37
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Default Re: Ampro Stylist projector

As you don't need the exciter lamp he's suggesting you remove the 50C5, but this requires altering the heater circuit to suit. A capacitive dropper can replace a resistor dropper. It eliminates the heat, but requires careful selection of capacitor type and value.

Upping the smoothing caps will reduce hum levels and decrease sag on transients, but I wouldn't do this unless a diode has been fitted. The elderly selenium rectifiers may not cope with the higher peak current. Fwiw the Ampro is not very hummy by cine projector standards.

I'd suggest playing the amplifier as is for a while and see how you like its tone etc. Some, or all of the above could be implemented at a later date, but do watch output anode and screen voltages.
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Old 19th Mar 2019, 2:14 pm   #38
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Default Re: Ampro Stylist projector

PS: Some heat would be saved if your isolation transformer can do 230v in 205v out.
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