Cyrus One

[hacknet]

with 75ma running through the output pairs, you should drop 16mv across each emmiter resistor or 32mv across the 2.

let see what happens when the new devices go in. apparently there is going to be a delay in the delievery because of the july 4th holidays!

what wrong with useing a 3055 for the output pairs, i thought they are just a spec under what the buv28s are rated. i am waiting for the mje243/253 to come in, is there any harm in running them off bd139/140 temporarily?

[sreten]

Originally posted by hacknet
hey guys!


.....another thing, i was thinking of scrapping the original supply altogether for a psx-lookalike..........

thanks a million!

Hi,

As far as I understand the original supply still drives the pre-amp
and power amplifier up to the driver stage with reduced ripple.

The PSX clone then just provides the juice for the output stage.
Voltage should be similar to the driver stage supply voltage.

sreten.

[hacknet]

yuppers! thanks for the advice man!

[anatech]

Hi sreten.

As far as I understand the original supply still drives the pre-amp

I'll check on that as well. The factory PSX delivers 40 VDC, the unit's own power supply is listed as 31 VDC. A quick look at a series 1 amp board shows the drivers share the same supply as the outputs.

I do know the supply inside the "1" powers the low voltage regulator section with the PSX connected. I am pretty sure the entire amplifier section is powered from the PSX on the Cyrus1 and 2.

To connect the PSX, just pull the fuses on the board first. Do not fail to remove them!

-Chris

[hacknet]

yeah, the entire power amp section is running off the psx, or the fuses for that matter. the preamp stage and the regulators are always on with or without the fuse.

[anatech]

Hi hacknet,
There is no point in rushing through anything. Just wait until you have the proper devices installed. TIP3055 and 2955 are just really poor devices. I wouldn't waste my time mounting them.

-Chris

[hacknet]

ohhh... okay.. i just didnt want to blow the more costly 711 to smitherins' over a silly mistake.

[anatech]

Hi Ken,

Anniken:

Are you talking to me?

If so, all my feelings are strongly suggesting you not repair the Mission amp. The design was seriously flawed to begin with. However, if you really want I will attempt to repair it for you to the best of my ability. I'll do the M-05 first.

-Chris

[anatech]

Hi hacknet,

i just didnt want to blow the more costly 711 to smitherins' over a silly mistake.

Do you have a variac you can use? A variable bipolar tracking supply would work. If you can get it running at + / - 20 VDC at least, you should be fine at the 31 V normal supply. Double inspect your work before you apply power, remove the flux from where you solder so you can actually see if you have a short.

-Chris

[hacknet]

thats the hassle, i dont have a variac nor do i have a bipolar tracking supply!

i quite worried that there is going to be a repeat of what happened to my 3055s.