White Oak- Phase Linear Driver Board Tester

[NavLinear]

Dennis I'm still trying to understand that, but is it saying you can custom cut a probe board to lower the driver(or any) board down on it and have all the test points accessible??

Yeah - that's what this system will do for you. We used to call these "Bed of Nails" as the probes were pointy and plentiful. Make sure you watch the short video on the home page of Merifix as it gives you an idea of how this system works.

This unit uses positioning posts (bottom plate) and hold down posts (pressure plate) to hold the board in place. The test probes are on the bottom plate and they are spring loaded as are the positioning posts. It would take some thought and time to build this but it should give you a reliable and repeatable test bed for the populated controller board.

I think Joe is building a test fixture similar to this one so he may be able to give you some additional inputs. One area of concern is where to put the positioners as there are only two mounting holes on the board - of course this was done to match the 400 and 700 mounting scheme.

 

[laatsch55]

Hmmmm........

 

[mlucitt]

I see the gears turning in Lee's head from here...

 

[laatsch55]

Bull gears, not pinions......

 

[laatsch55]

The bias ain't right......

 

[laatsch55]

After soldering test points, I indeed have a bad board. I hate it when 3 things go wrong at once.

 

[Gepetto]

Hi Lee
For this application, I use IDI spring loaded pogo pins on my fixture. The pin itself is Mouser PN 818-S-4-D-5-G and the solder cup, socket receptacle is 818-R-4-SC

The pins are replaceable within the socket receptacle.

You drill a mounting plate with the same X-Y pattern as the board to hold the pogo pins vertical. The easiest way to do this is to sacrifice 2 bare boards to the cause. The upper board is bored out to the diameter of the pin receptacles (larger diameter). The bottom board is bored out (smaller diameter) to allow the solder cups to pass through.


Then use M-F threaded standoffs to space the boards apart the appropriate distance. Use something like 534-7201 to separate the boards the appropriate distance and then use 534-1945 or 534-1944 below the bottom board to your fixture base and above to separate the BUT (board under test) from the fixture.

This is a simple construct that I have used repeatedly for programming and test fixtures.

 

[laatsch55]

Thank You Joe. I did do one thing wrong on my fixture, I did not run B+, B- to the collector andemitter output rails. Therefore all the current was trying to go through Q5, Q7, Q10 and they were getting real hot. So after work tonight I'll run those wires and see how we did..

 

[Gepetto]

that will give those poor little 2N3439's and 2N5416's a real workout Lee

 

[laatsch55]

Yeahj it sure was Joe. One of those head slapping moments, looked the fixture over again, perused the schjematic and thought " Ya dumbF*$#", it's gotta have some juice. Loaded it heated up in 3 seconds.

 

[Gepetto]

We've all had those moments Lee.

 

[mlucitt]

Lee, you built a space heater?!?

 

[laatsch55]

We've all had those moments Lee.

I seem to have enough for me and all my friends!!

 

[laatsch55]

Lee, you built a space heater?!?

Yeah, but it's none to efficient and awfully cranky.

 

[laatsch55]

I shelved the tester project for a day or so. I gotta find where the bass went on the right channel of the Larrt 700.

 

[NavLinear]

I seem to have enough for me and all my friends!!

You push it so that is to be expected. I mean that in a very good way and I'm grateful for being turned on to this site. We do need to get out of our comfort zone now and then.

 

[laatsch55]

Yeah, been that way all my life Dennis. Made winch trucks do some stuff they said couldn't be done moving drilling rigs.........among other oilfield oddities......I have learned to refrain from saying "Watch this" when pushing the envelope.

 

[NavLinear]

I could tell.

 

[laatsch55]

The board tester is a success, kinda scary lookin, but most prototypes that originate here are.

 

[NavLinear]

I love it - gotta work with what you have. I'm still referencing your many posts to plan out the tests I will do on my upgrades and fixes of all stuff audio. I know that I don't need to say this but keep it up - we watch and listen.