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Products => Test Equipment => Topic started by: Turbon on February 01, 2016, 06:10:12 am

Title: Kenwood HM-250 Distortion Meter Service Manual - where to find?
Post by: Turbon on February 01, 2016, 06:10:12 am

Hi.

I have been searching for one without luck and I have no ideas on where to look next.
Any leads would be welcome and apreciated.

I emailed the UK branch of Kenwood but I don't think they are the ones handling measurement equipment. Found that Texio Corp. seems to have taken over Kenwoods instuments. I have searched without succes and now emailed them but they have no references of HM-250(A) on their web.

Got an answer from texio jp informing me that they don't keep documentation on obsolete products  :(
So I have to tear it down and figure out how it works then if noone here can sell me a copy...

An updated - I have found that the Kenwood partnumber for the service manual is b51-1092-00.
Another upate. The earlier LEADER LDM-171 seem to look a lot like the HM-250. I believe I will have the meter on Monday to check if the boards are siblings. The LDM-171 service manuals are everywhere and the specs seems to be close enough if not the same.

Regards

Title: Re: Kenwood HM-250 Distortion Meter Service Manual - where to find?
Post by: Turbon on February 09, 2016, 04:30:31 pm

The Leaders is quite different inside so the partlists must differ a lot - no help. I'll put in some pic's of the HM-250 for your amusement

Regards

(http://i66.tinypic.com/5xmx79.jpg)

Quite clean...

(http://i67.tinypic.com/5mgj5.jpg)

Right side of PCB...

(http://i66.tinypic.com/1z5j31z.jpg)

Left side...

(http://i66.tinypic.com/2irngwn.jpg)

Bottom/trace side

If I can get this down to -100dB and find a way to stop the notch from drifting I would be glad. It's a nice little meter...

BTW, do you know what this is and maybe give a link to the data sheet :)...

(http://i66.tinypic.com/257py6q.png)

Optocoupler maybe?


Regards

Title: Re: Kenwood HM-250 Distortion Meter Service Manual - where to find?
Post by: radhaz on February 10, 2016, 12:50:50 am

The kana reads moririka. Looks a bit like a reed relay.
Some Kenwood instruments were rebadged Korean brands (or the other way round).

Title: Re: Kenwood HM-250 Distortion Meter Service Manual - where to find?
Post by: Turbon on February 10, 2016, 07:17:23 pm

Thanks radhaz. To bad I don't read kana  :(. All pages I find about moririka that seems to have information on the 5221 seems to be written in kana...

Regards

Title: Re: Kenwood HM-250 Distortion Meter Service Manual - where to find?
Post by: kipp on December 31, 2021, 07:54:15 am

this link to an expired auction describes the moririka 5221 as an optocoupler (フォトカプラー = fuotokapura = photocoupler).  https://aucview.aucfan.com/yahoo/w56405296/