Getting ready to do wopl 400 build

roccus · Aug 10, 2016

Thanks.. I do ask for sure when I'm not sure there is conflicting info out there on top of older builds to follow that are older rev. boards but I have tried to do all my home work best I could to prepare for this build I try not to bother you all with questions if I can find answers myself... glad I did not follow the directions to power it up without asking first... Getting a bit late to start building the PL14 so will just finish off day going over Joes notes and looking over all the pretty parts that will be going on the board...

NavLinear said:

Gepetto · Aug 10, 2016

roccus said:

The control board release notes go into great detail about the type and location of each output transistor on the first page.

roccus · Aug 11, 2016

Yes I see that Joe but it does not mention which one is PNP and which is NPN.... I'm going to build the pl14 board today get it connected so I can put power to this to start testing

Gepetto said:

laatsch55 · Aug 11, 2016

21196 are NPN, 21195 are PNP.

roccus · Aug 11, 2016

Thanks Nav gave me the answer a few posts back

laatsch55 said:

WOPL Sniffer · Aug 11, 2016

Looks like you are "down to the wire" (Pun Intended)...... Glad you are asking the experts, they got me through ALOT.... Can't wait to see it cranking.......

roccus · Aug 11, 2016

I have that feeling coming on everyone must get on the first one of these they build knowing power time is coming soon :shaking2:

... 1/4 watt resistors are all done onto the 1/2 watt

WOPL Sniffer said:

Gepetto · Aug 11, 2016

roccus said:

You should fully test the backplane and PS section before any attachment of the control board unless you like living dangerously. I always bring up PS alone first, then PS and Backplanes with minimum outputs and then finally all the above with control board. Safest way to success.

roccus · Aug 11, 2016

Confused now I posted yesterday was going to check backplanes as the way I understood directions but told here NOT to do it before putting control board in so that is why I am building control board now... so I DO test backplanes first right, put just the bottom row of transistors in??

Also on tech bulletin page about D4L/R still original 10ohm 1/4 watt resistor... this mean instead of installing diodes in D4L/R I use 10 ohm 1/4 watt resistor correct?? I noticed 2 of these were left over after finishing all the resistors

Gepetto said:

Billboard · Aug 11, 2016

Also when you bring the amp up to test the power supply positive and negative voltages don't forget to discharge the man storage capacitors, they will stay charged for days without the control board installed.

I used a 1000 ohm 20 watt resistor to do this, you dont need a 20 watt to do this, that is just what I had.

Gepetto · Aug 11, 2016

roccus said:

Hi Ray
You always check your work at each step. It is much harder to debug a problem when you do not know where the problem lies. Follow the bring up note that is included in the backplane instructions carefully.

You are building FULL COMP since you are installing the backplanes. Therefore this tech bulletin does not apply to what you are doing. There are 1N4148 diodes in each of the D1-D4 locations on each channel. You will note at the top of the tech bulletin it says "This note DOES NOT APPLY to FULL COMPconfigurations of this PCBA."

The documentation has to cover a huge waterfront of variations in the PL amps built over the years in combination of the quasi or full comp configurations now offered so please very carefully read to ensure you are building in accordance with your situation.

Hopefully this clears up any confusion.

Backplane bring up instructions:
With the connections to the control board all taped offso they do not short out to anything (both the bottom row of 10 wires and 3bias connection wires per channel).
Install the bottom row of transistors starting from the transformer, NPN, PNP,NPN, PNP. Remove the one wire to the upper left backplane 6-32 screw byremoving the securing nut and floating this wire in the air. Install railfuses. Check for infinite resistance between chassis groundand the transformer cases. If not debug. (you will get a readingbetween DC ground bus bar and these cases, you meter will be charging up thebulk caps)
Connect a ~10K resistor between the output and ground test point on eachbackplane.
Install rail fuses
Bring up on DBT and Variac to 60VAC in on the AC input. Make sure all isgood and no smoke is coming out. Measure that you have B+ and B- voltagespresent at the respective test points and B- at PAD12 and B+ at PAD 11 on eachback plane board.

Check that you have 0V at the output test point.

Take the Variac all the way up and repeat.

Next, before doing anything else, power the amp down and fully DISCHARGE thebulk caps using a 1K 2W resistor (any value close to 1K will do) down to alevel below 1V.

Then you are good to proceed to the next assembly step if this is all good.

roccus · Aug 11, 2016

"Remove the one wire to the upper left backplane 6-32 screw byremoving the securing nut and floating this wire in the air" Your talking about the star ground wire here right?

Gepetto · Aug 11, 2016

roccus said:

Yes, that is the only connection between DC ground and chassis ground. Lifting it should allow you to check for infinite resistance between the chassis and DC ground. An important check.

roccus · Aug 11, 2016

Thanks everyone for your help and input please bear with me a bit more I am getting this all sorted... almost got the pl14 board finished but we lost power for over an hour and a half was getting late and time for diner so will finish it tomorrow all that is left now are the large transistors electrolytics heat sinks and connectors

roccus · Aug 12, 2016

The phoenix connectors for control board from bias transistor Q6 on backplane boards... best to mount the connectors on top of the control board then run the wires on top to them or mount the connectors on bottom of board to keep things looking a bit neater??

Northwinds · Aug 12, 2016

We had some beasts of storms last night. Someone got hit by lightning here in Coventry. Another house got hit and started a fire and a bunch of trees down. We are supposed to get more today and they claim it will be worse... possible tornados. We seem to have a tornado every two years here in Coventry, I think we have had the most in the State since they have kept records

Yesterday, I did not even have to look at radar to know they were training and drifting south. I could hear every storm between here and the Mass border. All were full blown electrical storms

laatsch55 · Aug 12, 2016

roccus said:

The phoenix connectors for control board from bias transistor Q6 on backplane boards... best to mount the connectors on top of the control board then run the wires on top to them or mount the connectors on bottom of board to keep things looking a bit neater??

On the bottom...

Gepetto · Aug 12, 2016

roccus said:

As the pictures provided show Ray

13 pin on comp side
3 pin on solder side
all wire inlets facing down to board bottom edge

roccus · Aug 12, 2016

Thinking all is done except heat sinks does everything look ok? 12L1, 11L1, 16L, 12R1, 11R1, 16R.... those would be for original backplaines right?

roccus · Aug 12, 2016

This is the finished board and left over parts....

Getting ready to do wopl 400 build

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