getting ~4.39 instead of 5.333... help!

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acoustic warfare
 
Posts: 16
Joined: Thu Nov 15, 2007 10:41 pm

Re: getting ~4.39 instead of 5.333... help!

Post by acoustic warfare »

Hey there, i am also having the same problem....i have replaced D44 and D45 but no joy...

My Voltages are:

d44 d45 juncture = 0.55
d45 r5 juncture = 1.09
r5 tm6 juncture = 1.64
tm6 r4 juncture = 2.07
r4 d46 juncture = 3.32
d46 d47 juncture = 3.82
d47 r3 juncture = 4.36
r3 r2 juncture = 23.1
r2 r1 juncture = 26.0

Any help is much appreciated!

Thanks,

AW

adafruit
 
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Joined: Thu Apr 06, 2006 4:21 pm

Re: getting ~4.39 instead of 5.333... help!

Post by adafruit »

Check R1, R3, R4 and R5
then check them -again-
and then a third time.
The 6.8K resistor is often confused for 68K

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acoustic warfare
 
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Joined: Thu Nov 15, 2007 10:41 pm

Re: getting ~4.39 instead of 5.333... help!

Post by acoustic warfare »

Triple checked the R1-R5 and they are all fine (I built two PSU's at the same time and the other one is prefect).

I check the voltage on the LM336Z and the center pin is the same as the the 5.33 Volt output (around 4.5V), the second pin has about 2V on it, comparing this to the working PSU it should be 0V?

This is really bugging me, it is the most simple part of the x0x and i can even get it right..:)

The x0x is working fine apart from this one thing, because i cant get this right i cant tune x0xy.

guest
 
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Joined: Fri Feb 17, 2006 5:35 am

Re: getting ~4.39 instead of 5.333... help!

Post by guest »

if one of the lm366 pins is not 0v
then the connection to ground is flaky
try rehitting that joint

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acoustic warfare
 
Posts: 16
Joined: Thu Nov 15, 2007 10:41 pm

Re: getting ~4.39 instead of 5.333... help!

Post by acoustic warfare »

The rightmost pin (when looking at the LM336Z from the label side) has 0v on it. I tried rehitting the joints with the iron. no joy.

Maybe the LM336Z is faulty?

Would i be OK to replace it with the following IC?

http://www.jaycar.com.au/productView.as ... rm=KEYWORD

LM336-2.5 2.5V Voltage Regultaor

Thanks!

guest
 
Posts: 3155
Joined: Fri Feb 17, 2006 5:35 am

Re: getting ~4.39 instead of 5.333... help!

Post by guest »

it needs to be the lm336z-5.0
the last digits are for the voltage range

what is the voltage range it adjusts over now

808debris
 
Posts: 4
Joined: Tue May 05, 2009 7:59 pm

Re: getting ~4.39 instead of 5.333... help!

Post by 808debris »

Hello, im also having the same problem also...
this is one of my first projects soo.. im pretty confused on whats going on..

808debris
 
Posts: 4
Joined: Tue May 05, 2009 7:59 pm

Re: getting ~4.39 instead of 5.333... help!

Post by 808debris »

okay so i re-soldered everything and now im getting the correct readings..
now when i test the power supply i only get 10.4 rather then between 11.75 and 12.25 that im suppsed to be getting.

Danx
 
Posts: 11
Joined: Thu Sep 02, 2010 10:05 pm

Re: getting ~4.39 instead of 5.333... help!

Post by Danx »

Hi

Same problem here,on J4 i´m getting just 4.89 not 5.333 the problem is that i received a 220 PS (i´m on 120) so i made one my self 120VAC-9 VAC from a 120VAC -9 VDC 500mA(modified by removing all diod cap & res and direct connect to transormer) testing voltage on my self made PS gave me 10.01 v.
Here are my specs :

IC20 4.88
c3 12.70
c5 12.18

c1 6.04

IC23

4.82 0
4.89 4.89
4.89 4.89
24.8 10.96

IC22

0
4.80
1.73 to 2.27 (adjusting the TM6) (all grunded to regulator ic20)



D44-D45 0.53
D45-R5 1.05
R5-TM6 1.72
TM6-R4 2.26
R4-D46 3.83
D46-D47 4.36
D47-R3 4.89

Here´s the funny stuff:

R3-R2 14.01 and decrece to 0.70
R2-R1 17 and decrece to .70

Then i checked again but this time with supplied PS (220VAC 50 HZ 9VAC 500mA) which gave me a 5.5 V on multimeter test (half voltage required),
and i had the same results except that at R3-R2 there are not decresed or variable voltage standing at 12.80 and R2-R1 at 14.01

So i believe that i need to built a new PS,right?
The Transformer on my selfmade PS has a selector for 12,9.5,7.5,etc.
Sholud i try another voltage like 12v or even 14v? (direct conection from transformer 12 out give me 14 v on reading,9-12v,7.5-10,etc)

Thanks for your advices

guest
 
Posts: 3155
Joined: Fri Feb 17, 2006 5:35 am

Re: getting ~4.39 instead of 5.333... help!

Post by guest »

the powersupply you built
is probably still putting out dc
make sure all the components were removed

but once that is fixed
there is still an issue with ic22
make sure r2 r3 r4 and r5 are all the correct values
measure them with your multimeter

Danx
 
Posts: 11
Joined: Thu Sep 02, 2010 10:05 pm

Re: getting ~4.39 instead of 5.333... help!

Post by Danx »

I purchased a new PS 9 VAC 850 mA (Alesis) and send to fix the included PS from 220 to 120.Both new PS gave me 10.1 and 10.8.
With both m still having variable values on R3-R2,R2-R1 and IC23:
4.72 0
4.89 4.89
4.89 4.89
VAR 10.96

The only way i can get constant values is when i use a 9vDC 500mA PS...
R2- 2.1K
R3- 6.78k
R4-5.61K
R5-2.39K

Danx
 
Posts: 11
Joined: Thu Sep 02, 2010 10:05 pm

Re: getting ~4.39 instead of 5.333... help!

Post by Danx »

I have replaced R2 0.98K and R3 6.75K.

Still the same.

Can i continue on another section meanwhile?

Thanks

guest
 
Posts: 3155
Joined: Fri Feb 17, 2006 5:35 am

Re: getting ~4.39 instead of 5.333... help!

Post by guest »

you can continue on
but will want to fix it at some point

there have been a rash of bad ic22 lately
probably more technology transplant kits
they are out of specification

you can fix it by changing out r5 for a lower value

Danx
 
Posts: 11
Joined: Thu Sep 02, 2010 10:05 pm

Re: getting ~4.39 instead of 5.333... help!

Post by Danx »

I did that before (i saw that in some post) down to 1.5k instead 2.5K and didn`t see any improvement.
I`ll try it again anyway.

What happen if the voltage ends on 4.88 instead 5.333.....?
Is normal the variable dc reading that i`m having on certain points?

Danx
 
Posts: 11
Joined: Thu Sep 02, 2010 10:05 pm

Re: getting ~4.39 instead of 5.333... help!

Post by Danx »

Changed R5 2.4 for 1.5k......still having 4.88 on J4 and ic20.
Can i replace it with a lower resistance?

Thanks

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