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Vintage Tape (Audio), Cassette, Wire and Magnetic Disc Recorders and Players Open-reel tape recorders, cassette recorders, 8-track players etc.

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Old 7th Jan 2017, 11:20 pm   #1
Nightcruiser
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Default USA Webster 80-1 recorder

I inherited an American Webster recently model 80-1 that has been left unused for over fifty years.

Naturally I am not going to plug it in to try it out but i did want to do some preliminary checks as far as possible.

When checking the mains input pins on the machine, the meter is registering 10ohm and the alarm sounds for continuity when the set is clicked on at the on/off switch. On the ohms range i get a reading of around 12ohm

Given the design of this circuit, would this low resistance be caused by the two .05 capacitors going to earth or does this indicate something more serious such as a short circuit or burnt out transformer?

The machine is 125v.

I suspect the primary winding to be low but as yet i am to receive a comprehensive SAMS diagram with resistance measurements.

Your help and advice in the meantime would be appreciated.

John

Last edited by Nightcruiser; 7th Jan 2017 at 11:36 pm.
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Old 8th Jan 2017, 1:30 pm   #2
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Default Re: USA Webster 80-1 recorder

Quote:
or does this indicate something more serious such as a short circuit or burnt out transformer?
Or perhaps someone at some time tried to run it on 240V AC ?!
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Old 8th Jan 2017, 1:40 pm   #3
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Default Re: USA Webster 80-1 recorder

If your saying that the Primary of the mains transformer reads 10 Ohms that doesn't sound too far our to me for a 110V Primary rated at say 50VA?

I played with one of these back in the Early 80's they work surprisingly well.

Usual Lamp limiter and a step down transformer, see what transpires


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Old 10th Jan 2017, 4:11 pm   #4
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Default Re: USA Webster 80-1 recorder

It did occur to me that by mistake somebody may have previously tried to run it on 240v but there is no evidence of this so far. I just wanted to be absolutely sure as an all copper chassis using wire media and metal spools is not exactly my idea of fun and the SAMS photofact copy which has now arrived here isnt exactly clear. 🙁
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Old 10th Jan 2017, 4:20 pm   #5
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Default Re: USA Webster 80-1 recorder

Im trying to upload a photo of the model 80 circuit but having some difficulties
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Old 10th Jan 2017, 5:27 pm   #6
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Default Re: USA Webster 80-1 recorder

The current through the primary winding of a mains transformer depends not on its resistance, but on its inductance or more correctly its impedance. So it's quite likely that the 10 ohm reading is OK.
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Old 13th Jan 2017, 1:47 am   #7
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Default Re: USA Webster 80-1 recorder

Thank you Graham for your help. Much appreciated.
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Old 13th Jan 2017, 6:14 am   #8
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Default Re: USA Webster 80-1 recorder

Hi,

I know the Webster recorders very well, I have restored two in the past.

A few things to bear in mind with vintage American power transformers, in the Webster, or in any older American made appliances, is that they were designed for 60Hz use and the original designs, even on 60Hz, they ran high range peak flux values.

Running these old transformers on 120v & 50Hz, pushes the cores to very high peak flux densities, and they have a high primary magnetization current (the current drawn even with the transformer off load).

In scope gear and American TVs' this can also be a pest as the high radiated magnetic fields from the transformer core can upset the CRT beam, but with a recorder that is less of a worry unless there is pickup by the head, but they are well shielded.

It might also be that deterioration in the iron cores in the older USA power transformers occurs but this is not proven.

What this means is that you will probably find running this recorder on 120V 50Hz that the power transformer in the unit will run surprisingly hot. One thing to help is to lower the input voltage as much as you can get away with to 98-110 V range, or a mains voltage where you can just attain 6V on the heaters of the tubes rather than 6.3V.
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Old 22nd Jan 2017, 11:23 pm   #9
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Default Re: USA Webster 80-1 recorder

I have one of those model 80-1 recorders as well (it was my dad's)....the original manual states it can be run on 50 Hz current, but that recordings need to be played back at the same frequency as when they were recorded to ensure they'll be at the right speed.
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Old 23rd Jan 2017, 3:59 am   #10
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Default Re: USA Webster 80-1 recorder

Here's a scan of the schematic sheet to my model 80-1.
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