Eros malfunction [resolved]
- Thread starter Ascari
- Start date
Just a bit of an update. Since this was my only phon preamp, I invested in a cheap phone preamp that handles both MC and MM. The only cartridge I currently have is a Hana SL. When I connected it to my turntable and then to the Beepre via MM, I got the exact same response and I did on the Eros. Nothing... Keep in mind I have that connected to a external SUT. Once I pulled the SUT out of the line, the MC portion of the cheap preamp worked and I had how shall I say descent sound but no where near what the Eros could produce. Me Soundsmith cartridge is currently in for rebuild and is still weeks off, so I purchased a inexpensive MM to use as a spare. That should arrive in a few days, and I will check that on the MM part of the preamp. I think there is a chance that the problem my lie in the SUT, but it seems strange to me that both sides would go out within minutes of each other.
Just a note: I checked every single resister on both sides and they have all of the same voltage within a 10th of a volt.
With this info, any further ideas?
Just a note: I checked every single resister on both sides and they have all of the same voltage within a 10th of a volt.
With this info, any further ideas?
First thig to do is check to see of the Eros has DC on the input. Measure voltage across each RCA input jack center pin to jack outer shell with the Eros turned on. You should not see any significant DC voltage. Once you have verified this, check if the MC cart will also make sound directly connected through the Eros without the SUT in the circuit. Obviously it won't be as loud as you want, this is just to determine that the Eros is passing signal. If it works then check the continuity of each winding on the SUTs, and make sure the center pins of the RCAs on the SUTs haven't become grounded somehow.
I checked for DC voltage at the inputs and it was zero on both left and right. I put the EROS back into the system bypassing the SUT. There IS sound coming through the system, but is is very very faint at full volume. In the past when I had done this, I could get almost listenable music with the volume at 75%. Your correct that is not optimal. After checking the continuity of the SUT's I only had continuity on three pins out of 8.
OK, so as is often the case you seem to have two separate issues. You need to get the voltages right on the Eros, and also determine what is going on with the SUTs. An analysis of what connections might have been crossed when the tubes were swapped may help. I am headed out of town and have to run, but perhaps someone else can have a look at the pinouts and see if that could have created a problem.
Paul Joppa
Moderator
Ascari said:
OK, that's too high. Assuming you still get 4v at Kreg, the 2N2222 is not doing its job. Could be solder joints on the PC board.
----------- Added 2021 Jan 26 6:20PM -----------
Looking over the whole thread again, I see some problems on the 6922 socket (C) resistance measurements. You might re-check - it's tricky to get the right pin on those smaller sockets!
* Pins 4 and 5 are the heater, so one should be zero and the other less than 10 ohms; you said one zero and the other infinite
* pin 7 should be 75K, you said 0.
* pin 8 should be 27K, you said infinite.
I rechecked again this morning. First off the kregs were reading 3.9 volts and 4.2 volts. Haven't gone into the 2n2222's to check the solder connections yet. Either way the transistors are easy to replace. When I checked the 6922 socket this morning I was being super careful and did it from the component side came up with the following. I think we may be getting somewhere.
C1 46.8K
C2 75.4K
C3 27.8K
C4 0
C5 0
C6 46.8K
C7 75.4K
C8 27.5K
C9 0
I'm going to go in and reheat the solder joints to see if that changes things and let you know. If indeed the C4 socket is the culprit after so many years could it have caused a failure on the 2n2222's?
C1 46.8K
C2 75.4K
C3 27.8K
C4 0
C5 0
C6 46.8K
C7 75.4K
C8 27.5K
C9 0
I'm going to go in and reheat the solder joints to see if that changes things and let you know. If indeed the C4 socket is the culprit after so many years could it have caused a failure on the 2n2222's?
With the tubes in the sockets, C4 will show as 0 ohms. If the tubes are glowing, C4 is fine.
Not tube, tubes.
Any tube in any socket in an Eros shorts C4 to C5.
If the tubes are glowing, there's no issue there. EF86s glow so dimly that usually you need the lights off to even tell that they are glowing at all.
Any tube in any socket in an Eros shorts C4 to C5.
If the tubes are glowing, there's no issue there. EF86s glow so dimly that usually you need the lights off to even tell that they are glowing at all.
Paul Birkeland said:
I would get the metal can type. Jameco has a good supply of them.
The Eros is alive! i replaced the transistors and viola, voltages came back into line immediately. I know this was not an easy one, but with your help and persistance it is a success. You do know that I had just about convinced my wife for a Eros 2. Maybe for Christmas.
THANK YOU all for your help.
THANK YOU all for your help.
Thank you. That is not what actually happened, I didn't change any tubes until after the failure. Yes I did destroy a tube on the tube tester I know this thread is a bit confusing. None the less, it is working and that is all that I really care about. You have gone way beyond in helping me and for that you have you have a customer way beyond your expectations.
