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ε12 relay doesn't click

epsilon12

Re: ε12 relay doesn't click

Postby BMF » May 1st, 2016, 10:42 am

Relay with Power OFF:
Pin 1 to 16 = 0.0V, 2.84k ohms
Pin 4 to 6 = 0.0V, 0.0 ohms
Pin 6 to 8 = 96 mV, >1 M ohms
Pin 13 to 11 = 0.0V, 0.0 ohms
Pin 11 to 9 = 123 mV, >1 M ohms

Relays with Power ON (No Click):
Pin 1 to 16 = 150 mV, >1 M ohms
Pin 4 to 6 = 0.0V, 0.0 ohms
Pin 6 to 8 = 75 mV, >1 M ohms
Pin 13 to 11 = 0.0V, 0.0 ohms
Pin 11 to 9 = 60 mV, >1 M ohms

BTW,
1. although continuity was confirmed through the Molex connectors, I removed them and hardwired directly to the pads (V+ andV-, R/L IN, R/L OUT= No change
2. I also confirmed continuity between Pins 4 to 6 and between Pins 13 to 11 with the power OFF; there was also continuity between these pins with the power ON
3. There was no continuity between Pins 6 to 8 and between Pins 11 to 9 with power ON and OFF
4. I re-checked U1 Pins 4 to 8 = 22.8 volts; and each of these pins to e12 VG = 11.4 to 11. 6 volts
5. I re-checked +30 to -30 rails on EHHA Rev A = 59.6 volts
6. e12 V+ to V- = 59.6 volts
7. e12 trims down to 0.0 volts
8. There is no sound from my EHHA Rev A with e12 connected and powered ON...no surprise given all these measurements
9. After removing e12, my EHHA Rev A works just fine.

I conclude that the relay is not activating (and my hearing is OK) with power ON using both my e12s but I don't have a clue why not.
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Re: ε12 relay doesn't click

Postby amb » May 1st, 2016, 2:06 pm

It is not valid to be measuring resistance with a DMM in any circuit that's powered on. But anyway, it looks like your relay isn't getting activated because the circuit is in the "protect" mode where it has detected a large enough DC offset. You can verify this by measuring the voltage at U1 pin 1 relative to VG, It's probably higher than 0.6V (or -0.6V).

By default, something like 75mV or thereabouts of DC offset is enough to trigger the circuit into protect mode. Where your VG is 11.4-11.6V from the rails, that's actually a 200mV variance of the ground reference itself and is large enough to prevent the relay from activating. This is not to mention any actual DC offset from the amp outputs.

You may want to reduce the sensitivity of the circuit a bit, see the ε12 website Initial setup section, under "Notes".
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Re: ε12 relay doesn't click

Postby BMF » May 1st, 2016, 2:30 pm

Laughing at myself!

I'm new to this which is obvious to you and other more experienced guys.

I'll read the Notes about reducing sensitivity.

Thanks so much, Ti.

Keith

PS: U1 Pin 1 to VG = 0.95v
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Re: ε12 relay doesn't click

Postby BMF » May 1st, 2016, 7:16 pm

All that was needed was resetting the bias on EHHA Rev A! Now, e12 works / clicks.

Lesson learned: Never assume the obvious is OK.

Ti, thank you for all your help!

Keith
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Re: ε12 relay doesn't click

Postby amb » May 1st, 2016, 8:05 pm

Cool! :)
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Re: ε12 relay doesn't click

Postby salavat » April 13th, 2019, 3:42 am

I run into the similar problem, after I re-assembled e12 with its erroneous switches off.

1) Mine is v.1.2 (old one)
2) All transistors, diodes are as specified on the page
3) What is different (trying to rectify from relay activated during playback).
- R5-R8 are 15 kOm
- C5 is 3.3 uf 50V
4) Removed Q3 and Q4 - relay clicks. Q3 and Q4 checks OK on transistor tester (they are no burnt)
5) Supplying 12V rails from 2 lab power supplies chained together (+ and - from each ps)
6) Voltages, described in initial setup seem to be inline with suggested values (and other voltages described on this problem seem to be inline too)
7) C7 voltage does not increase and get anywhere close to 0.6V as described earlier.

I removed all transistors and installed new ones (found that I was using MPSA13) and D3 and D4, as well as new C5. Changed R5-R8 values from 75K to 15K from the partially working e12 (random switch offs).

Any idea?
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Re: ε12 relay doesn't click

Postby amb » April 13th, 2019, 4:06 pm

Salavat, is there anything connected to ε12’s inputs when you tested it? Did you adjust VR1 as described in the ε12 website’s initial setup section?

What’s the voltage at U2’s output (pin 6 for ε12 v1.2), relative to ε12’s VG?
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Re: ε12 relay doesn't click

Postby salavat » April 13th, 2019, 7:13 pm

Nothing is connected to e12. Yes, I followed initial setup adjustment for VR1.

While measuring U2 pin 6 I got something like -7.9V but I think I shorted U2, so now I get 0V on this pin.
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Re: ε12 relay doesn't click

Postby amb » April 13th, 2019, 7:50 pm

If you have 0V at U2’s output, then the relay should activate after a short delay when power is applied. The voltage across C7 should rise to about 1.2V.

What relay are you using?
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Re: ε12 relay doesn't click

Postby salavat » April 19th, 2019, 10:14 am

Ti,

Sorry for some delay. I recalled that I had some difficult problem with my beta 22 amp, the cure was to get new boards and install all parts on them. Basically, I've done the same with e12. It worked out from the beginning while powered from lab PS. Then I made some heatsinks for Q1 and Q2, tried to supply 29.8 V (that is what I have from sigma boards), confirmed that Q1 and Q2 do not get warmer than about 60 C, then connected everything (I soldered in and out wires) and put in the beta 22 case. Power supply is 2 rails from one of the sigma 22 boards.

Now relay does not click again ((. I've run through everything on initial setup page, except for that I get voltage not slightly over 24V (I have 25V and bit higher than that), other voltages more or less in line (with referenced 25 V) and dialing in and out I can get half of 25V on described spots. I have 16V voltage between specified pin and ground of sigma 22 PS.

What could be wrong?
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