400/1 “Linda” Full WOPL

[laatsch55]

Looking real good Andrew!

 

[AngrySailor]

Too late now Andrew but you could have avoided the milling of your hold down plate by mounting the bridge in the recommended rear hole (as pictured on the web page), not the front hole. When mounted in this position, the edge of the hold down plate almost comes in contact with the chassis side wall.

I did move the rectifier as you say, the one meter terminal was still VERY close to the plate (maybe 1/32”) so I just made a little extra room. I blew up one 400/1 meter already doing something stupid and took probably ten years to find another (thanks Lee).

 

[AngrySailor]

I should have measured while it was apart but what are the two meter ranges available by jumper and which position is which? Can’t find my original documents for the light board. I cranked it up a bit and hardly got the meters moving before my left channel (probably speaker issue) shut me down. Which position is which? Jumper on top or bottom for respective sensitivity? Have to fix a frozen pipe at a friends rn or I’d be diagnosing things...

 

[George S.]

Andrew, those blue LEDs, in the photos are throwing beams of light like laser pointers.
Good to see you back, and Linda up and running.

 

[AngrySailor]

Had a bad compression driver in the left cabinet. Was working but half melted VC and tone was way off. Speakers sound correct now, think I have issues with other components in the signal path. Did some signal generator testing. I’m going to do that again and write out the results to post later. The amp seems perfect though, there’s an imbalance somewhere before the amp...

 

[AngrySailor]

Andrew, those blue LEDs, in the photos are throwing beams of light like laser pointers.
Good to see you back, and Linda up and running.

They don’t photo well at all. Look much better in person...

 

[mr_rye89]

Yep. Pictures (taken with the Iphone 12 pro) of my meters look pee yellow, but they look incandescent in real life. Pictures taken with my Nikon D700 look more real to life. Phone cameras are still ass, still BTFO by a 15 year old DSLR.

 

[AngrySailor]

I was waiting to post until I got things figured out but I blew Linda’s right channel up doing some testing... drove the channel to near clipping and was taking some voltage readings in and out as I have an imbalance somewhere in my system and wanted to eliminate any possibility of the amplifier. Anyways I blasted the input voltage a little high by accident and clipped her real bad, blew the b- rail fuse... then of course being lazy, instead of bringing the dim bulb over to the amp, I slammed a new fuse in and let ALL the smoke out of the right channel... 4 blown output transistors, emitter resistors, bias resistor, r9&10 on the back plane r28 and a couple diodes in the limiter circuit on the driver board... Fug... It seemed the problem was with the driver board as bias was low but this ended up being related to the backplane. She’s back testing good now with drivers and one row of outputs installed. I’ve just tagged some components onto the backplane and driver board for testing, now that things are checking good I’ll start reworking the boards.

Have at me fellas, I’m a dumb ass!

 

[J!m]

"If a thing's worth doing, it's worth doing right."

 

[AngrySailor]

Geez, when I edit that post I changed a couple sentences around and forgot to mention Grapplesaw, he was a HUGE help with the diagnostics and repair. Sorry you got lost out of the original post!

 

[laatsch55]

Andrew, you're not the first or the last to do that...

 

[laatsch55]

Good job getting it squared away..

 

[AngrySailor]

Good job getting it squared away..

Thanks Lee. I’ve actually enjoyed fucking up as It forces me to learn much more about the driver board. Couple questions... r9&10 1 ohm resistor on the back plane, it was in Kohm range so I bridged a 10 ohm across. Replaced blown emitter resistors on xq 5&6 with original pl400 emitter resistors. Only xq 5&6 are populated rn.

can I use the .22 ohm PL emitter resistors for now and are the 1ohm r9&10 only used as a bridge/jumper? What is acceptable there until proper parts are here?

thanks all

 

[AngrySailor]

Good job getting it squared away..

Lots of help available here...

 

[Gepetto]

Thanks Lee. I’ve actually enjoyed fucking up as It forces me to learn much more about the driver board. Couple questions... r9&10 1 ohm resistor on the back plane, it was in Kohm range so I bridged a 10 ohm across. Replaced blown emitter resistors on xq 5&6 with original pl400 emitter resistors. Only xq 5&6 are populated rn.

can I use the .22 ohm PL emitter resistors for now and are the 1ohm r9&10 only used as a bridge/jumper? What is acceptable there until proper parts are here?

thanks all

R9 and 10 will work as 10 ohms temporarily however should be 1 ohm after you get things squared away

 

[AngrySailor]

R9 and 10 will work as 10 ohms temporarily however should be 1 ohm after you get things squared away

Thanks Joe, I’ll be ordering stuff for a 700b soon, your kits for Tim and Linda had a few extra goodies that really helped. Couple extra diodes and resistors but man, did I ever blow this up...

 

[AngrySailor]

Edit/caveat: ENTIRELY MY FAULT

 

[AngrySailor]

Looking at swapping crossovers with pops... his is stereo 3 way which will allow me to use both Tim and Linda along with the monster carver. Hoping to get Linda patched up tonight enough to test drive then I’ll have to modify the speaker jacks on the three way cabinets to separate the 15’s from the passive crossover which will only be used for the mid/horn split.

 

[AngrySailor]

She’s alive... got original PL emitter resistors one channel and I still need to get a few resistors to bring things right back to spec.

 

[George S.]

Way to go Andrew. I'm also looking forward to your 700 S1 build. You've the most awesome system in the Province!