SP 12 SE

[laatsch55]

Joe you have a knack for picking the nights I get in late. If your game , so am I, Just finished with kitty cuddles and Jani just handed me dinner. Give me a few Joe and I'll be ready. Yep got some 300K's. No on the TIP50. What exactly does the TIP 50 do??

 

[laatsch55]

Joe, I'm not 100% sure the artwork matches the schematic. Considering how some of this other stuff went can't guarantee it is. THAT I will check. Pic coming up.

 

[laatsch55]

For your perusal Sir.

 

[Gepetto]

Hi Lee
The TIP50 is a current amplifier to increase the current output capability of this otherwise wimpy LR8 TO-92 regulator. It performs an emitter follower function on the voltage that is regulated by the LR8 device. The output of the TIP50 emitter is the LR8 voltage less 0.65V.

 

[laatsch55]

Current amp makes a lot of sense. I got a dozen of each when I ordered.

 

[Gepetto]

Hi Lee
Double check the values of R22 and R23. Can't really tell from the photo but the color bands look odd. R22 is supposed to be 1.5K and R23 is supposed to be 330K. No color band on the R23 position looks like orange-orange-yellow in the photo

 

[Gepetto]

R22 kinda looks like brown-green-brown (150 ohms) in the photo you sent to me but the multiplier band is a bit fuzzy so cannot tell for sure. should be brown-green-red (1500 ohms)

If this resistor is really 150 ohms, this will never pull into regulation.

 

[laatsch55]

It's faded like most MO's seem to be. IT IS 1.5 k, observed and pulled one leg and measured. R23was/is 330K. Linked in series-upright with a 100K.

 

[Gepetto]

Thanks Lee, could not really tell from the photos...

 

[laatsch55]

In goes the 300K and out comes the TIP50, forthwith.

 

[Gepetto]

Timer board parts ordered tonight Lee...

 

[laatsch55]

Good Deral Joe. Ok with TIP 50 out and 300K in place of 330K and 100K in series we get bullshit----because my test point failed.


Had you not posted tonight, the Eico was going in circuit.


take that with a grain of salt. one of the B+ leads that I left off the phono boards had the wire nut fall off. This was the B+ feed to the phono board from the main board. The bare lead was touching the "Audio Barrier".

 

[laatsch55]

Still the same after re-wire-nutting the B+ feed .

 

[laatsch55]

Input on the LR8 388.6 volts DC, output on the LR8 regulator is 245 voltsDC----with TIP 50 out and 300K in R23.

 

[laatsch55]

I think I know how the rest of this will go. Put the TIP back, verify 245 and go back with the 330K.

 

[laatsch55]

Verified 245.8 volts at output of LR8. 246.9 after 1 minute. Verified 246.4 at the emitter of the TIP 50.

 

[speakerman1]

Is that good? LOL I'm sorry to be such a pain.

Larry

 

[laatsch55]

Larrt, were I you I would have fired my ass. You are not being a pain buddy. BTW--those were VERY good numbers. Might even get the AP on it tonight.

 

[speakerman1]

It is called learning. I use to be good at one time. First mech job. Was trouble shooting a landing gear problem. Found a bad diode on the control card. We didn't have a spare card. We swung the gear with my fix. The guys that had years on me put a Beach 99 gear handle in a Beach 1900. Took it on a test flight. In flight emergency on landing. Gear wouldn't come down. It was the 99 gear handle. I had to fill out so much paper work. I was the sign off mech.

Larry

 

[laatsch55]

Did you think it was your diode switch??