Yu Fong YF-600 schematic

[Miguel Lopez]

Hello

I'm searching for the schematic of the Yu Fong TF-600 clamp meter. I have fixed one of them and I want to adjust it. In order to move the right potentiometers I need the schematic. I just have found this page:

https://www.olx.ua/obyavlenie/tokoi...lamp-meter-yf-600-made-in-taiwan-IDkCT9Y.html

But the schematic in that page is not clear and I can not see components values and identification.

Any help welcome

PS. I know I could use the trial and error method, but I want to be more professional with a little help from my friends.

 

[Harald Kapp]

This museum website (German, sorry) allows downloading of documents.

Click on the image in the upper right, the photo of the instrument changes to a schematic representation. Click on this representation to download the document. A popup will open which asks you to enter some information:

Enter the information as shown, mark 'Ich bin kein Roboter' (I'm not a robot) and click 'Schaltplan (Unterlage) anfordern' (request download of schematic).

I hope this helps.

Saludos,
Harald

 

[Miguel Lopez]

Thanks Harald. I'm a member of RadioMuseum too, but I have not found the YF-600 there.

 

[Harald Kapp]

Follow the 1st link (1st line) in my post #2, it will lead you directly to the page where I took the screenshots from.

 

[Miguel Lopez]

I did it, but as I told you, that is not the one I'm looking for. I'm after the YF-600 which looks like this:

 

[Harald Kapp]

I'm sorry, my fault. I was careless in checking the number.
Unfortunately that was the only hin to a YF-meter schematic I could find.

 

[73's de Edd]

.

Ehhhhhhhhhh . . . . . Senor Miguel Lopez . . . . . . ¿ que paaaaaaaaaaaaaaaaaasa ?



Well since you have the manual, you can make out the fine print number designations and R assignments.
Let me just roughly reference its aspects and you relate and read the numbers.
As for any adjustments, we can first eliminate the ORANGE box where we have the full scale OHMS
trim adjustment, for compensating for battery strength decline.OHMS function only.
The BLUE box would be an AC calibration adjustment for your AC ranges, as it is feeding down to the meter rectifier.
The GREEN box would be the cal adjustment for that far left current range , with each fixed resistor progressively shunting it as you work up through greater current ranges to the right.
Any corrective calibration in the SPECIFIC individual other ranges, would be dependent upon changing its relevant shunting resistor value by resistor replacement.
The PURPLE semi box would be for the sole DC scale on the unit, its another situation of changing its value
if calibration is needed on that sole DC voltage range .
The very last cal adjustment to be seen is the meter ZERO adjustment within the RED circle.
Identifying the two pots would just be related to the interconnections of specific adjunct components to them.

MARKED UP ILLUSTRATIONS



73 s de Edd

 

[Miguel Lopez]

Thank you very much