• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

CR-800 Pre-Amp Issues?

avionic said:
index.php
The two black ones in the center of the photo look like the plastic has shrunken a bit.
Click to expand...

From left to right those two measured ~50.3uF and ~91.2uF (and low ESR) so should still be good. Checked the diode and resistor that run between them and diode was ok and resistor still about 2.2k ohms.
 
Check C801-807.. You may have already checked two of them..If you haven't already . Check FR802..
 
Last edited:
If the board has power going to it. There is at least one fusible on that board.
 
*I think* I correctly found C801-807. When I zoom on the SM I can't read the numbers very well. But, there were two 10uF capacitors (both 80X something I think). They formed an "L"...both measured around 12.6 uF, however one had a low ESR and the other was likely borderline high (it was a 10uF 35V one). Outside of that all checked out.

I'll work through the other fusible and see what I find tomorrow. Appreciate all the help!
 
avionic said:
I'd go through and check all the fusibles in there...
Click to expand...

Finally got through the fusibles:
FR801=OL
FR802?=4.4ohms (directly below D801 from trace side)
FR803=226.9ohms (cracked shell)
FR804=4.4ohms
FR805=4.3ohms
FR806?=220ohms (connects to C817)
FR807=4.5ohms

I think those are correct number from what I could make out on the fuzzy zoom of the SM. Looks like maybe one or two are off based on SM...not sure which is which though.

And going over the SM I'd say it may not hurt replacing most/all as values have drifted just over >10% on several. Is their original tolerance 10% or 5%?
 

Thank you! Which of these should be 47ohm? FR801 and one other? Or are all the small ohm values supposed to 3.9 (I'm going off the list at the back of SM for FR values)? I will get my order in asap so I can see if/what else goes off the deep end.
 
So some of my numbers vary from the back of the SM. Looking at the schematic it makes more sense, sort of. Here is where I sit and what the schematics says they should be (parenthesis are measured values):

FR801(OL) = 1/2w 47ohm; HW40447
FR802 (4.4) = 1/2w 220ohm; HW41339
FR803 (226.9) = 1/2w 47ohm??; HW40447
FR804 (4.4) = 1/2w 3.9ohm; HW40339
FR805 (4.3) = 1/2w 3.9ohm; HW40339
FR806 (250.2) = 1/2w 220ohm; HW40522

My HW numbers aren't perfect crosses with the SM--I'm confused since the SM lists two 220ohm resistors, but the schematic does not (but I have two resistors that measured as though they were supposed to be 220ohm...see FR803). What should I follow (schematic, SM list, or removed values)? SM also lists some amperage specs but the schematic does not, just wattage.

Thank you again!
 
You must log in or register to reply here.
Back
Top Bottom