On 10/11/2018 8:41 PM, geoff wrote:
On 12/10/2018 3:21 PM, Paul wrote:
Where can I get a replacement Board for an Event Electronics Tuned
Reference Monitor TR-5?
One of my TR5s went bad, with very low volume, so I cracked it open
(after swapping speakers, to make sure that was not the problem).
Unfortunately, I was not able to find a schematic online.
At first I thought maybe the LM3886TF audio ICs went bad, but after
doing some signal tracing, it appears the input signal isn't making
it to differential input pins 9 and 10, on either of the ICs.Â* Or
at least, the signal is much attenuated from the input level.
Also, the heat sink that the LM3886TFs are bolted to, is getting a
little bit warm, and the +/-24 Volt rails are at pins 1 and 4. So this
makes me think maybe the LM3886 chips are NOT the culprit here (they
also do not look melted, damaged, or cracked).
Perhaps there is a bad passive component in the cross-over circuitry?
Or maybe the TL072C Opamp is bad?
At any rate, does anyone know where I can get a replacement board?Â* Does
Event still support this older model?Â* Could they replace, or at least
troubleshoot this board?
Or does someone have a schematic?Â* I'm lost in the forest without one!
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If no or very low signal to the power amp chip inputs, then look further
back. Sure, change the TL072 might be first option, that is after
checking for fractures at input socket connections to PCB and thereabouts.
You could maybe try www.eventelectronics.com for spare parts or service
info.
Ok, never-mind everyone. I'm 99.9% sure I found the problem!
The sensitivity/gain pot had the center wiper lifted, so it was
an open! When I shorted the center lead to the high gain lead, my
sig gen was loud and clear! And I could hear the crossover working,
as the sound went from woofer to tweeter as I increased the frequency.
I believe this is a linear taper (not log) pot, 2KB.
I hope my electronics place has one with similar physical
dimensions, when I go there tomorrow morning.
Hurray!
