It appears my Eros has given up the ghost. When I turned it on today, no sound. The Beepre is fine. After checking, at least one of the E86 tubes was bad. In the process of checking, I destroyed the second. (Don't Ask) Since I had a spare set I installed the spare and viola it was working again. At least I think so. After a few minutes I realized only one channel was working. Hmmm. I played around a little bit and swapped tubes from side to side. Guess what? Neither side is working again. My guess is something has failed and blowing the tubes. There is about 3,000 hours on preamp. OK time to start with the basics. Where should I start? I'm thinking it is the right hand channel but not sure.
Eros malfunction [resolved]
- Thread starter Ascari
- Start date
Measure voltages. Use the tubes that you think are blown. Check to see if they are glowing. The glow is very faint, you will need the lights out to see it. Once you have established if they are glowing do the voltage measurements. Report any that are off from the manual.
A failed component usually gives a pop and a puff of smoke. You may just have a loose connection in the amp, which may be revealed by a voltage check. It's entirely possible that your tubes never had an issue, especially with only 3000 hours.Ascari said:
I just got the manual dug out and will start this afternoon. As an FYI, there was no smoke or "pop". I was listening to music the day before and had not issues. The next day, there was not output from the Eros. I checked the tubes on a tube tester and at least one was showing a short. Can't say about the other since I accidentally put the tube into the wrong socket on the socket which resulted very bad settings. It went off like a flash bulb. For some reason it also shows a short. Anyway, I check out the extra set using the appropriate socket and settings and let you know what it says. I will also let you know the various voltages as well.
Thanks
Paul
Thanks
Paul
That could definitely cause some damage.Ascari said:
The plot thickens. I checked all of the resistance at the rails and they were in a hair's breath of the original settings. As far as the tube sockets, they too were pretty much the same except for one resistance on the c socket. One had gone up about 6K Ohms. I left the numbers upstairs and will get those toy you. All of the DC voltages were in normal spec and all 4 led's lit up on the three boards. Now for the interesting part. I rechecked all of my tubes. (I have a B&K dynascan tube tester.) Except for the one that I blew up, the other three showed good. I came back down to my system plugged everything back in. Put on a record and I got sound out of both channels, however it was very low at full volume. The longer I left it on, the quieter it got. The turntable I am currently using has a low output MC with a passive sut. I purchased the sut from a gentlemen on eBay who makes them. It is about 4 years old. I thought it might be the SUT so I by passed it plugged the directy into the Eros. There was no change in volume. In fact it was dead silent. As an fyi, prior to purchasing the SUT I used the same cartridge with the EROs and got descent volume but just not enough. Finally just to rule out any issues with the Beepre, I moved the Eros ouput to my CD input on the Beepre. No change.
Diminishing signal output would generally mean that voltages are moving around. You'll need to capture voltages after this has happened and we can help you determine what might be going on.
I plugged the unit in and took an initial DC Measurements. I then waited for about 10 minutes and took them again with no change.
Right Left
Kreg 4 volts 4 volts
Ob 137 V 137 V
bA 0 V 0 V
breg 137 V 136V
Oa 142 V 142 V
Ia 219 V 219 V
With those numbers I decided to double check my resistance measurements on the tube sockets
I discovered a potential issue.
Socket A Socket B
Pin # 1 27 K 27K
2 0 0
3 75K and climbing 3K and climbing
4 Infinity Infinity
5 0 0
6 75.1K 75.2K
7 0 0
8 Infinity Infinity
9 47K 47K
Socket C 2299
1 46.8K
2 75.3K
3 26.8K
4 Infinity
5 0
6 46.8K
7 0
8 Infinity
9 47K
Right Left
Kreg 4 volts 4 volts
Ob 137 V 137 V
bA 0 V 0 V
breg 137 V 136V
Oa 142 V 142 V
Ia 219 V 219 V
With those numbers I decided to double check my resistance measurements on the tube sockets
I discovered a potential issue.
Socket A Socket B
Pin # 1 27 K 27K
2 0 0
3 75K and climbing 3K and climbing
4 Infinity Infinity
5 0 0
6 75.1K 75.2K
7 0 0
8 Infinity Infinity
9 47K 47K
Socket C 2299
1 46.8K
2 75.3K
3 26.8K
4 Infinity
5 0
6 46.8K
7 0
8 Infinity
9 47K
Can you post some build photos?
The 4V you have at both Kreg pads is a bit strange, which tube got plugged into which incorrect socket?
The 4V you have at both Kreg pads is a bit strange, which tube got plugged into which incorrect socket?
I would go through and be sure things like the leads of the 47K resistors aren't touching other leads that cross over/under them.
The 4V at Kreg means that the DC servo is trying to pump the brakes really hard on letting the EF86s draw any current, but your 6922 plate and cathode voltages are almost shorted together, which makes me suspicious of the wiring.
The 4V at Kreg means that the DC servo is trying to pump the brakes really hard on letting the EF86s draw any current, but your 6922 plate and cathode voltages are almost shorted together, which makes me suspicious of the wiring.
I checked the 47K resistors and all of the other resistors and wiring about the plate. It all looks good and nothing was touching etc. Looking very closely with a bright light, it all looks good. In addition, I took a shot and installed a fresh 6922 tube. The voltage at the kreg dropped to 3. By the way when I explained that I put a tube into the wrong slot, that was not on the Eros, but my tube tester. I will continue to trouble shoot as best I can. Like I mentioned before, this has been working for 9 or 10 years. I have not done any wiring on it for that amount of time except for adding some Mundorf caps years ago. I can continue to review the wiring which will happen, but something tells me it is a possible component issue.
Thermioniclife
Member
Man it sure looks like those large resistors are shorted to that smaller resistor passing under them. Are you sure they are not touching?
PJ may have some other ideas about what's going on, otherwise you may need to send it in for repairs.
Paul Joppa
Moderator
I agree with PB, the bias servos are not working.
The relevant resistors are on the B side of the board; R3 is the small 174-ohm resistor and R4 is the larger 27K. You have reported 137v at breg (which is connected to R4) - what is the voltage at the other end? It should be around 0.7 volts. You should see the same voltage at the end of R3 nearest R4. Can you check those voltages?
The relevant resistors are on the B side of the board; R3 is the small 174-ohm resistor and R4 is the larger 27K. You have reported 137v at breg (which is connected to R4) - what is the voltage at the other end? It should be around 0.7 volts. You should see the same voltage at the end of R3 nearest R4. Can you check those voltages?
