emud: 176; Rekord

Gentlemen,

 

First, I hope everyone had a merry Christmas and a happy holiday no matter your religion and belief.  Now, down to hobby business. 

 

I have an Emud Record 176 ( US version I believe.  Mains volts set at 110v only) and no German lettering.   I used a schematic for a 186, 196.  However, there is a difference between the mains on the primary of the schematic to actual circuit wiring. 

 

The difference on this chassis is one of the power cord/mains conductors (before the primary on the power transformer) is connected to the chassis (through the power switch).  I found this while locating the RF bypass caps.  I use UL rated safety caps.  I double checked this with an ohm meter and measured minimal resistance from one of the non-polarized plug tongs to the chassis.  It is a good thing that I checked this with an Isolation Transformer.

 

Is this intentional?!

 

I have requested the schematic for this radio under the model number on this web site.  But, until it is posted could/would someone look up the schematic for this unit and let me know how the mains power cord is supposed to be wired to the primary?  OR email to me or post a schematic?  And not to be too demanding, are there alignment instructions available?

Thanks in advance,

Paul.

PS - I attached a picture of a new way I opened up and gutted the can capacitor.  I am sure many of you have this specialty tool that I used.

Attachments:

• Record 176 under chassis (85 KB)
• Open a can cap (85 KB)

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Hi Paul,
I loaded a schematic that I got on CD before years. After reading you question I looked into the schematic and see a dangerous problem. One line phase is directly connected to frame-ground.
So it is also connected to ground side of phono input! A safty-cap goes from ground to earth connector and to middel of phono input. So this is as dangerous as an AC-DC radio!!!!!!
I prefere to cut the connection from primary to frame-ground, or replace it by 5nF savety-cap.

Update after intervention from Mr. Pinyot and Mr. Knoll:
I forgot to look for Anode-Voltage. It will not work if the wire is cut. So it is best to protect Phono input from using, as modern phono players will feed the ground to chassis.


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In dieser Schaltung ist eine lebensgefährliche Verbindung!! Eine Netzphase ist mit dem Chassis verbunden!  Nur die Erdbuchse und die Mitte der Phonobuchse sind über einen 5nF Kondensator gekoppelt. Phase liegt direkt an der Phonobuchse.
Ich empfehle die Verbindung vom Netz zum Chassis zu trennen, oder durch einen 5nF Kondensator zu ersetzen. Der sollte aber den VDE-Vorschriften entsprechen!

Änderung nach Hinweis von Herrn Knoll:
Da der Trafo keine Wicklung für die Anodenspannung hat, sondern nur ein Heiztrafo ist, darf die Verbindung nicht getrennt werden.
Ich empfehle daher den TA-Eingang abzudecken, da Plattenspieler meist mit dem Chassis an dem äußeren Masse-Stecker hängen, und nicht wie früher am Mitttelstecker.

safty first!
Heribert Jung

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Heribert,

I looked at the schematic you uploaded.  That is disappointing.  There is no High Voltage secondary.  They used rectified line/mains voltage for the B+.  And the circuit ground is connected to the chassis as evident by the riveted ground lugs through out the chassis. 

I suppose the best I can do is use safety caps where there could be a hot to chassis short like the 5nF across the EZ80 and the 5nF (lower right) from the front end to ground.  I will add a polarized plug to help insure the chassis side is connected to neutral mains. I do not have an old transformer, with a proper secondary, to scavenge for this chassis.

I wonder how much an add-on isolation 1:1 transformer would cost?

Thanks again for posting the schematic.

Paul.

 

 

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Hallo Herr Jung.

Wird diese Verbindung getrennt, spielt ja das Radio nicht mehr.

 

Der Anodenstrom fliest ja wie beí einem GW Geraet im Primaerkreis also im Netz.

Siehe Philettas. Das war in diesen Jahren zulaessig, es gibt hier im RMorg, einen Bericht Grundig 960 oder so. www.radiomuseum.org/forum/grundig_960_musikgeraet_problem_mit_stromversorgung.html

 knoll

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Sie haben Recht, Herr Knoll.
Es fehlt die Sekundärwicklung für die Anodenspannung. Es ist nur ein Heiztrafo.

Danke für den Hinweis.

Heribert Jung

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Herr Jung,

wenn ich das Packet des Trafos ansehe, denke ich, der hat Netztrennung. Nur Paul sieht da eine Unterschied zwischen der Inlands und US-Version was sein kann oder nicht.

Anfangs konnten solche Bomben nach USA verkauft werden, dann kam UL mit dem Stopp.

Ich wuerde das von Paul klaeren lassen bevor Sie ins Messer laufen.

 

knoll

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Dear Paul,

$15.99 is the answer plus postage.

This is the only safe way even with your 120V supply!  See below on ebay buy-it-now.

http://cgi.ebay.com/117-VOLT-TUBE-AMP-MIXER-PREAMP-ISOLATION-PWR -XSFMR-T90_W0QQitemZ9718209188QQcmdZViewItem

js: edit of link because of "exploding" frame.

Happy repairs for the New Year,

Roy

 

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Gentelmen,

The schematic posted on the web site does not represent what I observed in the chassis.  The  Rekord 176 (note the spelling)  schematic has the circuit ground connected to the chassis through a 5nF cap.  The actual radio, Record 176, has rivets on the chassis with numerous component wires soldered to them.   An ohm meter proved a closed circuit from the power plug to the chassis.

Does anyone have the schematic for the Record 176 US version that could verify my observations and please report back here? 

I suppose that I should trust my observations.  But I am a rather detailed "nit picker".

Roy, As per your recomendations, I  also recomend using an isolation transformer with this unit.

Thanks,

Paul.

 P.S.  More Pictures at 

http://www.ppinyot.com/E/emud.htm

 See bottom of page for the Record 176.

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Hi Paul,
you are right, the Chassis is connected to line directly !
You are right it is dangerous without isolation transformer.
The schematic is a little confusing. The long line from top of the 5nf left to the right side with the 2 50µF Elkos is the Chassis. Chassis is ground.

The ground symbol left under the 5 nF shows the external earth connection. If you look fine, there is a connector symbol under the 5 nf like it is under the antenna symbol.
The earth symbol can be plugged in like the antenna.
The earth connector is wired  to the middel of phono input, which was used as phono player frameground.

The 700pf at antenna is also safty critical.

I hope the rest of the schemaic fits also to your radio.
Maybe there is a Sam's Photofact for this radio.  Here www.justradios.com/ 
you may get a Photofact, if it was printed for this model.

Happy new Year,
Heribert

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Heribert,

I shall check for that 700pf cap.  I must have missed that one. 

And the Emud web site pics are still uploading. 

Thanks,

Paul.

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