How To Measure Crack Resistence And Voltage?

[jazzfan78]

hello. i finished build my crack and now i need to measure things up
i have UNI-T UT33D Multimeter. i put the red lead in the center and the black one in com is it ok?
anyway i dont know in resistence and voltage what to choose. i have few options that i marked in the picture. and if someone can tell me how to measure . do i need to put the black lead on ground (on the metal chassis plate) and the red one on the terminal? or should i put them toghter on the terminal? thnx for help

picture:

http://i60.tinypic.com/2ef2wis.jpg

[Chris65]

Hi. Yes that is the correct : black lead to COM & red lead to the V/ohm position.
I would also suggest alligator clip leads as this makes testing easier & safer.
For resistance, set the meter to the range appropriate for the reading you expect, for example if you expect 22kohm, set it to the 200kohm range as you won't get a reading on the 20kohm range as the expected resistence is above that.

The black lead is attached to chassis ground & the red lead put on the appropriate terminal to get a reading.
There are Youtube tutorials showing how to use a multimeter, watch a few to get a good idea.
Also, please read the manual instructions & warnings about voltage testing - if you're not sure, find someone to help.

[jazzfan78]

well i check and results are not so good...

Terminal Resistance
1 *   (ok- no change)
2 *    (0.00) ?
3  0 ohms  0.00
4 *              (0.00) ?
5 *              (14.05) on 20k option
6   2.4K ohms    (2.50) 
7  2.9K ohms      (2.50)
8 0 ohms            (0.00)
9   2.9K ohms     (2.49)  show sometime 17.49 and dissapear
10 2.4K ohms     ( 2.49)
12 0 ohms           (0.00)         
13 * will climb slowly toward 270K ohms  (climb to 196 and stop)
14 0 ohms (0.00)
20 0 ohms (0.00)
22 0 ohms (0.00)
B3 2.9K ohms   (13.16) and dissapear in 20k option
B6 2.9K ohms (13.97) and dissapear in 20k option

RCA jacks:
Ground lug 0 ohms - (0.00)
Center pin 90K ohms—100K ohms 
LEFT 106.3
RIGHT 103.4

[Paul Birkeland]

Here's something to start with. Try to measure the resistance of one of the 3K resistors. 

If you can measure 3K across a 3K resistor, then measure the resistance between T3 and T8 (it should be quite low).

What do you end up with for these numbers?

I see that you have some reasonable measurements, but if you really have 0 Ohms on 2 and 4, there are major construction issues in the amp. 

-PB

[jazzfan78]

i have the crack+ speedball the 3k resistors is not installed.

correction:

2 *    (0.00) ? go up to 17.25 and dissapear
4 *              (0.00) ? go up to 18.25 and dissapear

pic:

http://i60.tinypic.com/2nu7ul1.jpg

[Paul Birkeland]

i have the crack+ speedball the 3k resistors is not installed.

There are no resistance measurements in the Speedball manual, the assumption is that you started with a working Crack before the upgrade, and therefore can move along to voltage checks.

-PB

[jazzfan78]

well after speedball instalation i suppuse resistence results will not be the same. so what should i do? should i go to voltage test?

in crack guide its written that its unforbidden to move to voltage tests if resistence tests is not ok

[Paul Birkeland]

Yes, the next step after completion in the Speedball manual is to do voltage checks.

-PB

[jazzfan78]

After ordered new resistors
Vishay dale 22.1KOHM; 1W; 1% - RESISTOR, METAL FILM

and removed the speedball. this is only the crack resistence checks to see whats wrong.

Terminal Resistance
1 *   (ok- no change)
2 *    (0.00) ?
3  0 ohms  0.00
4 *              (0.00) ?
5 *              (ok- no change)
6   2.4K ohms    (2.49) 
7  2.9K ohms      (2.93)
8 0 ohms            (0.00)
9   2.9K ohms     (2.96)
10 2.4K ohms     ( 2.48)
12 0 ohms           (0.00)         
13 * will climb slowly toward 270K ohms  (climb to 200 in 200k option and stop- didnt find any option to go up to 270)
14 0 ohms (0.00)
20 0 ohms (0.00)
22 0 ohms (0.00)
B3 2.9K ohms   (2.93)
B6 2.9K ohms  (2.96)

RCA jacks:
Ground lug 0 ohms - (0.00)
Center pin 90K ohms—100K ohms 
LEFT 106.3
RIGHT 103.4

[jazzfan78]

?

[fullheadofnothing]

When a terminal is marked with an asterisk, the big thing to look out for is that they don't read zero. Several of yours do, so you need to examine the wiring carefully against the manual. Post pictures if you can.