400 Series II LED Board

[Lou_Prime]

I have a 400 that I have rebuilt as full comp with the White Oak boards. When I purchased the amp it was not working and someone had attempted to do a repair on the LED boards and had lifted traces and otherwise made a mess of it. The amp is now working and sounds great but the LED boards are not functioning correctly based upon the behavior of my other 400 Series II. The channel B board, instead of showing a solid dot, displays three individual bars and the bars were in the middle of the display rather than in the left hand corner. The channel A board's display was a mess which I partially resolved by replacing a faulty transistor (thanks Joe). This resulted in it displaying in the same manner as the B board - better but not quite right.

I compared my boards to the boards pictured in the service manual and they are not the same. My boards only have two transistors, Q301 and Q302, and they are both TIS97. R304 is 10K on the B board and 1M on the A board. The leg of R306 that should be grounded per the schematic is not connected. Also, changing the value of R306 has no effect on the display.

I'm guessing that these are early model boards and without a schematic and/or a parts list I'm pretty much out of ideas. I'm hoping that someone is familiar with this iteration of the LED boards and can provide me with any information that they may have or tell me that the boards are working as designed (wouldn't that be grand).

Thanks!

 

[Northwinds]

Welcome to Phoenix!

Ed (Oldphaser) should be able to help you out and probably has the parts also. He is here weekly so hopefully he will see this. I think White Oak has LED boards now also?

 

[oldphaser]

I have a 400 that I have rebuilt as full comp with the White Oak boards. When I purchased the amp it was not working and someone had attempted to do a repair on the LED boards and had lifted traces and otherwise made a mess of it. The amp is now working and sounds great but the LED boards are not functioning correctly based upon the behavior of my other 400 Series II. The channel B board, instead of showing a solid dot, displays three individual bars and the bars were in the middle of the display rather than in the left hand corner. The channel A board's display was a mess which I partially resolved by replacing a faulty transistor (thanks Joe). This resulted in it displaying in the same manner as the B board - better but not quite right.

I compared my boards to the boards pictured in the service manual and they are not the same. My boards only have two transistors, Q301 and Q302, and they are both TIS97. R304 is 10K on the B board and 1M on the A board. The leg of R306 that should be grounded per the schematic is not connected. Also, changing the value of R306 has no effect on the display.

I'm guessing that these are early model boards and without a schematic and/or a parts list I'm pretty much out of ideas. I'm hoping that someone is familiar with this iteration of the LED boards and can provide me with any information that they may have or tell me that the boards are working as designed (wouldn't that be grand).

Thanks!

There were indeed a number of revisions to the LED style meter drive boards. Not all of them were documented. I have the original prototype that was used in the 400 series II amp as well as some like the one you described. When repairing these boards they need to be repaired as a matched pair. In other words, the semiconductors (most notably the transistors) should be of the same manufacturer, same part number and same batch. Differences in the parts can cause linearity issues such as not tracking equally between both channels. If one half of the meter display is having issues and not the other half, the problem will be with the UAA170 I.C.

There is more to this that might be best discussed over the phone.
Send me a PM with your number and I will call you.

Ed

 

[WOPL Sniffer]

Joe at White Oak now has the 400/700 Series II LED boards on his site and I have used them and they are the BOMB.... They work excellent and look just like the originals.... I will use them again soon. Plus, they are economically priced and will probably outlive the amp.



http://www.whiteoakaudio.com/estore.aspx


Perry

 

[Gepetto]

Joe at White Oak now has the 400/700 Series II LED boards on his site and I have used them and they are the BOMB.... They work excellent and look just like the originals.... I will use them again soon. Plus, they are economically priced and will probably outlive the amp.



http://www.whiteoakaudio.com/estore.aspx


Perry

And they are DC coupled throughout the design. Just like the amp. The originals were not.

Plus you get more bits of resolution with the White Oak boards. 40 LEDs vs 36.

 

[WOPL Sniffer]

And they are DC coupled throughout the design. Just like the amp. The originals were not.

Plus you get more bits of resolution with the White Oak boards. 40 LEDs vs 36.

Dang Joe, yer gonna spoil us. I know on my 700 Series II WOPL the meters worked sweet and it was pretty easy to install even for a chucklehead like me.......... Some of the guys I built amps for wanted to know why I didn't warranty the meters and I said "There are no parts to rebuild the originals and if you want to spring for new WO meters, I will gladly warranty them if I do the install". So, I got a couple guys mulling the new meters over. WELL WORTH IT.

 

[Lou_Prime]

I had an informative conversation with Ed and I'm going to do some troubleshooting. If I am then unable to get the boards working I'll go with new boards as I don't want to invest a lot of time or money into the existing boards.

 

[WOPL Sniffer]

I had plenty of issues with some of the series II LED boards, and a few of them had corroded leads on the LED segments just be careful lifting them out of the sockets. Also, the posts that the power comes into the boards had cracked solder joints. The Rectifier circuit is in the right board and feeds DC over for the left side. If both boards are doing the same thing, the power (the AC or the DC) would cause that. If you have a segment failure (both sides would USUALLY not act the same), you'll NEVER find replacements. I went through that search for 2 years. The driver chips are available. Otherwise, there isn't much else to those boards and $130 for a pair of boards from Joe is a way better option than dicking with those old boards. I also changed out the electrolytic caps on those originals but the segments were shit so I just bought new WO boards.

 

[Lou_Prime]

Finished

After a recap and some other trouble-shooting I decided to stop throwing good money after bad and bought the replacement boards. The LED's now dance as they should and the amp still sounds terrific.

I have an original 400 in the queue that is going to get the full-comp treatment but that will have to wait until I finish up some other projects I've been working on. I am looking forward to watching the meters on the 400 and my RT-707 do their thing.

 

[MarkWComer]

I suppose these new meters need to be calibrated in some way- is this easy to do?

 

[laatsch55]

Joe built em Mark......

 

[WOPL Sniffer]

I suppose these new meters need to be calibrated in some way- is this easy to do?

Piece of cake to adjust them. I've used a couple sets. If you can build a WOPL, doing the adjustments is not an issue Mark

 

[MarkWComer]

Piece of cake to adjust them. I've used a couple sets. If you can build a WOPL, doing the adjustments is not an issue Mark

Yeh, didn't and don't expect it to be a big deal.
Just taking note that the same meter boards can be used for the 400 and the 700, something has to be adjusted!

I didn't see anywhere on the WhiteOak e-store about this, but are there any color options for the LEDs?
The new dark laser etched PL700 faceplate with blue LED meters... Groovy combo!

 

[WOPL Sniffer]

Yeh, didn't and don't expect it to be a big deal.
Just taking note that the same meter boards can be used for the 400 and the 700, something has to be adjusted!

I didn't see anywhere on the WhiteOak e-store about this, but are there any color options for the LEDs?
The new dark laser etched PL700 faceplate with blue LED meters... Groovy combo!

Joe doesn't make a 700 Series II faceplate (Only 700B). You need to talk to Joe

 

[MarkWComer]

Joe doesn't make a 700 Series II faceplate (Only 700B). You need to talk to Joe

Somebody does- for the 700/II. I know I saw them, forgot where...

EDIT: Sorry, it was someone who had used faces for sale, not new ones.
(Post: WOPL Sniffer;224855)

 

[Gepetto]

Yeh, didn't and don't expect it to be a big deal.
Just taking note that the same meter boards can be used for the 400 and the 700, something has to be adjusted!

I didn't see anywhere on the WhiteOak e-store about this, but are there any color options for the LEDs?
The new dark laser etched PL700 faceplate with blue LED meters... Groovy combo!

From the eStore Mark...

[TABLE="width: 1135"]
[TR]
[TD="class: style25"]PL400/700 Series2 Cylon LED Meter Board Kit (Pair)[/TD]
[TD="class: style26"] PL400_700_S2 LED METER KIT[/TD]
[TD="class: style26"] B[/TD]
[TD="class: style26, align: right"] $131.00[/TD]
[TD="class: style26, align: right"] $160.00[/TD]
[TD="class: style26"] Yes[/TD]
[TD="class: style26"] Yes-USPS Priority Flat Rate[/TD]
[/TR]
[TR]
[TD="class: style25"] PL400/700 Series2 Cylon LED Meter Board Assembly (Pair)[/TD]
[TD="class: style26"] PL400_700_S2 LED METER ASSY[/TD]
[TD="class: style26"] B[/TD]
[TD="class: style26, align: right"] $231.00[/TD]
[TD="class: style26, align: right"] $260.00[/TD]
[TD="class: style26"] Yes[/TD]
[TD="class: style26"] Yes-USPS Priority Flat Rate[/TD]
[/TR]
[TR]
[TD="class: style25"] PL400/700 Series2 Cylon LED Meter Board Kit (Single)[/TD]
[TD="class: style26"] PL400_700_S2 LED SGL METER KIT[/TD]
[TD="class: style26"] B[/TD]
[TD="class: style26, align: right"] $70.00[/TD]
[TD="class: style26, align: right"] $99.00[/TD]
[TD="class: style26"] Yes[/TD]
[TD="class: style26"] Yes-USPS Priority Flat Rate[/TD]
[/TR]
[/TABLE]

 

[Gepetto]

Yeh, didn't and don't expect it to be a big deal.
Just taking note that the same meter boards can be used for the 400 and the 700, something has to be adjusted!

I didn't see anywhere on the WhiteOak e-store about this, but are there any color options for the LEDs?
The new dark laser etched PL700 faceplate with blue LED meters... Groovy combo!

Red is standard and what is priced Mark. Other colors are available with discrete LEDs instead of the LED array modules, pricing will vary with color choice. The kit allows both.

 

[MarkWComer]

Red is standard and what is priced Mark. Other colors are available with discrete LEDs instead of the LED array modules, pricing will vary with color choice. The kit allows both.

Red array modules it shall be!
Don’t wanna take the chance of it looking like a mouthful of crooked teeth...