Author Topic: Ts500 not working

February 04, 2021, 06:54:22 PM
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Dsa

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Hi There

  Im new here!

Ive just build a Ts500 unit and connected it to my 51x Rack built by Igor (Ij Research) step 1 in the test didnt work :

OV to V+ showed 15.70 but OV to V- showed no value at all and also no connection when connected to the case.
and also Resistor R41 smoked and turned dark(so iguess its fried now)
first of all im wondering if there is a possible problem with the rack case (there are to JLM LA500a and an NV73 working just fine in there but those are all 51X so would there be a difference?) or what possible mistake could i have done?
and should i worry for the rest of the unit components now?
I've added some pictures of the assembled unit and with the connections in the case and also the Extender i was using:
https://photos.app.goo.gl/VdnZmGzUitRm5EtB9

The unit passes sound through when "off" but it doesnt when on "mute" or "on"
i have the other kit lying around i am wondering if should try and build to trace any possible mistakes or figure out if the case has something different than expected

any help will be appreciated!
Thanks!
D

February 05, 2021, 03:54:42 PM
Reply #1

JPK

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Remove U12.
Check R50 & R51 in circuit (1R). They should look almost like shorts.
Check R41 in circuit (33R). If open circuit, replace.
Check V+ and V- by powering very shortly each time (1 or 2 seconds).

Check the DC volts on TP7. Should be around -200mV.
Check the DC volts on TP6. Should be at 0V.
Reflow any suspicious joint.
Brush the PCB to remove any unwanted solder bits.
JPK

February 07, 2021, 10:24:40 PM
Reply #2

Dsa

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Hey JPK

Thanks for the help

Ive tried and there is a bit of a difference but the unit is behaving the same thought the is a bit of a light flash on the two first yellows when turned on
these are the results so far:

(i am using a automatic digital multimeter Avtek 020053, should this be a problem?)

R41 (33r) - still closed although a bit darkened but value as should be

0v and v+  = 15.80 v (i guess ok)

0v and v - = 0.8  v :(

0v and Tp7 - 15.93 k-ohms

0v and Tp6 :
when off - ascending values from 110 k-ohms up until 130 but then i turned it off
when mute - 47.3 k-ohms
when on - 1.6 k-ohms

I've also strengthened a few suspicious joints before these tests

Any other idea?
Thanks
D




« Last Edit: February 07, 2021, 10:29:48 PM by Dsa »

February 08, 2021, 12:14:48 PM
Reply #3

JPK

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Quote
0v and v - = 0.8  v :(
Can you check V- in the rack?


Quote
0v and Tp7 - 15.93 k-ohms
0v and Tp6 :
when off - ascending values from 110 k-ohms up until 130 but then i turned it off
when mute - 47.3 k-ohms
when on - 1.6 k-ohms
I was asking for volts, not ohms.

JPK

February 09, 2021, 06:51:07 PM
Reply #4

Dsa

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so.....All working great! :

This is what i think happend: 

My soldering at first was not good enough, so when i connected the unit the -16v fuse burnt in the power supply but it did not bother the other modules since they use + - 24v, i kept trying to troubleshoot the unit and aperentaly as soon as i replaced the fuse the ts500 works perfect and sounds amasing 8)

Thanks for the Support JPK!


February 10, 2021, 10:14:40 AM
Reply #5

JPK

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JPK