[r1seals]

Hi all I would like to know if any one has pictures of the out board supply for these tables  I know that Frank had done this in the past but what he has in the audio basics is for the T-60 and the T-25 and T30 has the transformer on a little board, and that little board has wires to the drive motor and the switch that tells it to start and return I would just like to know how to wire the thing up any help or pictures of the table and box would be great  thanks
 Russ 

[rlee8394]

Check the Audio Basics 1985 PDF available on the avahifi.com web site. It's at the end of the document. Rebuild of the HK T-60.

[r1seals]

Check the Audio Basics 1985 PDF available on the avahifi.com web site. It's at the end of the document. Rebuild of the HK T-60.

 yea I have all the audio basics letters but like I put in the first post that was for the T-60
 not for the  T-25 or T-30  anybody still have one of these old tables that Frank did back in the day?

[avahifi]

OK, I will try and help you with the outboard supply for the HK T30 turntable.  I have a few quiet moments this afternoon so I pulled mine from my system and removed the cover to see what I did with this 25 years ago.

I removed the power transformer and its attached small circuit board all together from the turntable and mounted them together in the small chassis box on a couple of 3/4 inch long threaded #6 hex spacers, using the transformer mounting lugs.  The board hangs below the transformer.,

I also mounted a single chassis fuse holder on the top of one of the transformer lugs and a terminal strip with two ungrounded lugs on the other transformer lug.

Connections are as follows:

Hot side of AC in to one side of the fuse holder - the side closest to the shorter protruding end of the PC card.

From the other side of the fuse holder connect a wire to eyelet 501 (which on my unit has a metal tab connected here),

Connect the ground side of AC to eyelet 502.  There also is a ceramic disk capacitor (probably 0.01uF at 1KV) connected between lugs 501 and 502.

Use a simple 5 amp rated toggle switch to turn the box on and off.  Connect a wire from lug 503 on the board to the input of the switch.

Connect a wire from the output of the switch to eyelet 504 on the board.

Connect a wire from eyelet 505 on the board to one lug on the terminal strip.

Connect a wire from the other lug on the terminal strip to eyelet 501 on the board (along with the wires from AC ground and one side of the .01uF capacitor just added).

Connect a 120V neon indicator lamp across the terminal strip, one lead to each lug where wires were just connected.

Moving to the other side of the PC card, connect a wire from eyelet 512 to the positive side of a 10,000 uF 16V electrolytic capacitor.

Connect a wire from eyelet 511 to the negative side of this capacitor.

Connect a wire from the positive side of the capacitor to the hot (inner) terminal of a panel mount RCA jack.  Note that the jack should be mounted with insulating shoulder washers on the panel of the chassis box to isolate it from chassis ground.

Connect another wire from the negative side of the big capacitor to the ground side of the RCA jack.  You will need a 1/4 inch solder lug for this purpose.

Test it.  It should read +12V DC at the RCA jack and the neon should light up with the power switch turned on.

Note that I actually used 4 x 10,000uF at 16V in my box.  The supply is very very quiet and very very stable.

Other than this, the instructions in the December, 1985 issue of our Audio Basics apply.  The only stock parts on the PC card remaining are the power transformer, D501, and capacitor C502.

Oh yes, you will need to make a long shielded cable terminated in an RCA plug to interface the external 12V supply to the point inside the turntable chassis where the output of the PC card previously connected to the turntable motor and anything else important.

Best regards and good luck with the project.  I had not looked inside mine for 25 years and the turntable still runs just fine and very very quietly and stably.

Frank Van Alstine

[roscoeiii]

And what are the strengths and weaknesses of this table sonically Frank?

Also, do you recall whether there is much sonic difference between the t55 and t60?

[avahifi]

OMG, I did this 25 years ago!  My T-30 is a decent and very, very quiet turntable with a good arm and has run perfectly for years and years and years.  It cost about $100 new!

Mine is equipped with our Longhorn Gold phono cartridge and is certainly good enough to allow us to easily hear differences in prototype phono preamp design ideas.

Can you do better?  Almost certainly!  Do I care?  Nope.  Its just another test tool here.  No problems, easy to use, and semi-automatic to boot.  The purpose is the music, not to see how much money and how many gismos you can throw at it.  I did the external power supply because the stock unit was not compatible with a Grado cartridge because of hum issues.  The external supply fixed that completely.

Regards,

Frank Van Alstine

[Brett Buck]

OMG, I did this 25 years ago!  My T-30 is a decent and very, very quiet turntable with a good arm and has run perfectly for years and years and years.  It cost about $100 new!

     I got mine about then, and aside from needing a new belt a few years ago, it just keeps going. Nothing to do, it just works.

      Brett

[r1seals]

OK, I will try and help you with the outboard supply for the HK T30 turntable.  I have a few quiet moments this afternoon so I pulled mine from my system and removed the cover to see what I did with this 25 years ago.

I removed the power transformer and its attached small circuit board all together from the turntable and mounted them together in the small chassis box on a couple of 3/4 inch long threaded #6 hex spacers, using the transformer mounting lugs.  The board hangs below the transformer.,

I also mounted a single chassis fuse holder on the top of one of the transformer lugs and a terminal strip with two ungrounded lugs on the other transformer lug.

Connections are as follows:

Hot side of AC in to one side of the fuse holder - the side closest to the shorter protruding end of the PC card.

From the other side of the fuse holder connect a wire to eyelet 501 (which on my unit has a metal tab connected here),

Connect the ground side of AC to eyelet 502.  There also is a ceramic disk capacitor (probably 0.01uF at 1KV) connected between lugs 501 and 502.

Use a simple 5 amp rated toggle switch to turn the box on and off.  Connect a wire from lug 503 on the board to the input of the switch.

Connect a wire from the output of the switch to eyelet 504 on the board.

Connect a wire from eyelet 505 on the board to one lug on the terminal strip.

Connect a wire from the other lug on the terminal strip to eyelet 501 on the board (along with the wires from AC ground and one side of the .01uF capacitor just added).

Connect a 120V neon indicator lamp across the terminal strip, one lead to each lug where wires were just connected.

Moving to the other side of the PC card, connect a wire from eyelet 512 to the positive side of a 10,000 uF 16V electrolytic capacitor.

Connect a wire from eyelet 511 to the negative side of this capacitor.

Connect a wire from the positive side of the capacitor to the hot (inner) terminal of a panel mount RCA jack.  Note that the jack should be mounted with insulating shoulder washers on the panel of the chassis box to isolate it from chassis ground.

Connect another wire from the negative side of the big capacitor to the ground side of the RCA jack.  You will need a 1/4 inch solder lug for this purpose.

Test it.  It should read +12V DC at the RCA jack and the neon should light up with the power switch turned on.

Note that I actually used 4 x 10,000uF at 16V in my box.  The supply is very very quiet and very very stable.

Other than this, the instructions in the December, 1985 issue of our Audio Basics apply.  The only stock parts on the PC card remaining are the power transformer, D501, and capacitor C502.

Oh yes, you will need to make a long shielded cable terminated in an RCA plug to interface the external 12V supply to the point inside the turntable chassis where the output of the PC card previously connected to the turntable motor and anything else important.

Best regards and good luck with the project.  I had not looked inside mine for 25 years and the turntable still runs just fine and very very quietly and stably.

Frank Van Alstine

Frank thanks for your time to do this for me I appreciate it lot's I think I can get on with the project now, if it was the T-60 I would not have a problem with what you put down in Audio basics but when looking at the guts of the  T25 and t30 just wasn't same.
 again thanks for your time
Russ

[trackball02]

Russ,
Are you getting a lot of hum with your T25 and T30?
I recently got my T60 running after many years in storage. Replaced the belt and installed a Grado Reference cartridge. Had a local stereo shop go over the unit and it runs great. Good speed and no hum very quiet even towards the end of the record with the tonearm closest to the motor.  You many want to see if you have any problems before going through the upgrade.
Jay

[WGH]

A few years ago I did the power supply upgrade on my T55C, the result was even greater speed stability and a more focused center image. The mod was easy to do so I would say go for it even if you don't have any hum problems.

Wayne

[r1seals]

A few years ago I did the power supply upgrade on my T55C, the result was even greater speed stability and a more focused center image. The mod was easy to do so I would say go for it even if you don't have any hum problems.

Wayne

yea Wayne I was looking on the circle at your pics of the box and the bottom of the turntable good pictures the only thing that has me a little baffled is I have a blue and white wire that runs to the switch of the tone arm and don't know what to do with them ?
 Yea I am going to do this project as soon as I get the parts  ya know the only cart.that hums is the Grado  now my audio technica 440 mla doesn't  oh well soon it won't

[WGH]

the only thing that has me a little baffled is I have a blue and white wire that runs to the switch of the tone arm and don't know what to do with them ?

Do you have the T25 service manual from Vinyl Engine?
http://www.vinylengine.com/library/harman-kardon/t25.shtml

It looks like the blue and white are 120V wires to the SW1 micro switch. After the mod the DC from the new power supply could go through the micro-switch first and then to the motor (red +).

On the PCB-2 board remove C501 and jumper the two points that the blue and white wires connected to.
The new .01uF ceramic disk capacitor connected between lugs 501 and 502 functions the same as C501.

Wayne

[r1seals]

On the PCB-2 board remove C501 and jumper the two points that the blue and white wires connected to.
The new .01uF ceramic disk capacitor connected between lugs 501 and 502 functions the same as C501.

Wayne
[/quote]

Dang Wayne guess I missed that sure as s--t   and yea I do have the service manual and while I had the thing open took some good pictures of things.

[WGH]

You are getting the general idea. The service manual doesn't have the eyelets numbered but I'll guess 503 and 504 is where the blue & white wires were attached? If that is true then no jumper is needed, since mine doesn't have a circuit board it is wired a little different.

Connect a wire from lug 503 on the board to the input of the [toggle] switch.

Connect a wire from the output of the [toggle] switch to eyelet 504 on the board.

[r1seals]

You are getting the general idea. The service manual doesn't have the eyelets numbered but I'll guess 503 and 504 is where the blue & white wires were attached? If that is true then no jumper is needed, since mine doesn't have a circuit board it is wired a little different.

Connect a wire from lug 503 on the board to the input of the [toggle] switch.

Connect a wire from the output of the [toggle] switch to eyelet 504 on the board.

tell you what Wayne  if i can post pics might help,  well have to put them in my gallery first I'll try and do that tomorrow and thanks for your help and everybody  else 
Russ

[AVA convert]

Russ, just hook the blue and white wires to the red and black wires and it will be all done