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December 03, 2020, 05:32:37 PM

Author Topic: Smashup A side LEDs don't light up [resolved]  (Read 4150 times)

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Offline antoineestephan

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Re: Smashup A side LEDs don't light up
« Reply #15 on: September 14, 2015, 04:10:52 AM »
I would start by replacing both transistors on the offending side.  If you can't find them locally, they can be ordered from us or any online electronics retailer.

-PB
Hi
I did order a batch of MJE5731A from Amazon and I expect to receive them in about 10 days, as that was the reference of the transistor we were talking about all through This topic. But today I looked closely to my boards and found that the transistors in my smashup have the reference MJE5731G!! In the smashup manual it just says MJE5731!
So it was like I got a cold shower, please tell that both have the same specifications and are interchangeable.
By the way I couldn't find any MJE5731G on Amazon

Online Paul Birkeland

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Re: Smashup A side LEDs don't light up
« Reply #16 on: September 14, 2015, 06:17:32 AM »
They are interchangeable in the Smash-up.  I would also replace the PN2907's.

-PB
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline antoineestephan

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Re: Smashup A side LEDs don't light up
« Reply #17 on: September 21, 2015, 07:43:32 AM »
Oops, PB, I found a problem
Turned out that I soldered one lead of the 2 joint resistors of R2 in a wrong whole, the one that's inside the R2 rectangle on the board.
Now my LEDs are all glowing
Any way some wrong voltages on that same board, which is now on the C side:
Terminal.           A.                C.   
IA.                     194.5V.         194.5V
OA.                    148.5.         193.5
+reg(A side).          2.49.          2.48
IB.                     148.5.          195
OB.                      70.              59
Kreg (B side).          4.25.           1.89
Breg.                   148.5.           162.
+reg.                   148.5.           162


B1.        0V
B2.     148.5 V
B3.         4.4V
B4.          0
B5.         59
B6.           1.88


Hope it's getting simpler now to diagnose the rest of the problem!
Thanks for your patience

Online Paul Birkeland

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Re: Smashup A side LEDs don't light up
« Reply #18 on: September 21, 2015, 08:25:04 AM »
Breg and OA are connected together, they shouldn't differ by 20 volts.
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline antoineestephan

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Re: Smashup A side LEDs don't light up
« Reply #19 on: September 21, 2015, 09:00:27 AM »
Breg and OA are connected together, they shouldn't differ by 20 volts.
Thanks.
Will recheck later.
 I just re read galyons post and it seems that my problem is similar to his, anyway in that post the dialogue is too technical for me, and couldn't understand all of it, to try to take voltage readings off the same points.
His problem was solved by replacing the regulators.

Offline antoineestephan

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Re: Smashup A side LEDs don't light up
« Reply #20 on: September 23, 2015, 05:07:06 AM »
Breg and OA are connected together, they shouldn't differ by 20 volts.
Hi,
redone my readings today and you were right
 Breg +reg and IB all read 201V, OA : 201V, Kreg ( B side) :1.86V, B5: 66V, and B6: 1.86V
All others read within specs.

Online Paul Birkeland

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Re: Smashup A side LEDs don't light up
« Reply #21 on: September 24, 2015, 11:20:30 AM »
Hi,
redone my readings today and you were right
 Breg +reg and IB all read 201V, OA : 201V, Kreg ( B side) :1.86V, B5: 66V, and B6: 1.86V
All others read within specs.
B5 connects to OA, which indicates that there's still a measurement issue.

In situations like this, it really helps to triple check everything in the manual, and resolder all your joints.  Having these voltages differ when they are basically on a solid piece of wire may suggest loose connections.
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline antoineestephan

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Re: Smashup A side LEDs don't light up
« Reply #22 on: October 15, 2015, 04:13:43 AM »
B5 connects to OA, which indicates that there's still a measurement issue.

In situations like this, it really helps to triple check everything in the manual, and resolder all your joints.  Having these voltages differ when they are basically on a solid piece of wire may suggest loose connections.
Hi
It's been a while, I actually was sick, I was in and out of the hospital and haven't looked at my smash for about a month.
Today I took a look and there it is, instead of attaching the red wire in 9U to IB I attached to OB, rectified it and voilà everything checked within specification.
Now I'm listening and it seems that sound from left speaker is not as good as the one from the right. I'm investigating it, but all in all I'm happy.
Thanks PB especially for your patience