Datasheets of 1980's/90's Marcon and IC electrolytic caps
I am looking for the datasheet of the original electrolytic capacitors used in a Rowland Consummate preamp. Due to the age of the preamp (nearly 30 years) I want to replace the electrolytics. I would like to look up the specs of the originals before deciding what to replace them with.
There are 3 different types:
4 x 1000uF/25V marked IC LBAM M85{degree}C 2K07A
12 x 6800uF/35V marked Marcon AWF-M20 +85{degree}C 3B08A
6 x 100uF/63V marked IC RMRM B105{degree}C 22
Thanks,
Albert
PS Long read, below.
I have an old (1992/93) Rowland Consummate preamp that I have used for >20 years. A few years ago it developed a problem (DC on output of both channels). I contacted Rowland and they suspected a fault in the gain modules. Living in Australia, sending the unit to Rowland was not an option. Subsequently the diagnosis was done by email. No new gain modules were available and I put my preamp into storage.
A year or so later I was able to buy replacement NOS gain modules from Rowland. After installing them I had no sound at all. Swapping to my own (defective?) gain modules resulted in a working preamp, for a while. Then the dreaded DC on output was back. This was getting weird!
A few things are worth mentioning:
1. The problem started after we had weeks of severe thunderstorms. I normally switch the equipment off during storms, but may have been too late during the last one.
This originally led me to think about possible spikes or other mains power issues during the storms. I live in a rural area, we have overhead power lines and power failures are common during storms.
Could the storm have killed both my gain modules?
2. According to Rowland, it is rare for a gain module to develop a problem. To have 2 gain modules develop the same problem at the same time seems very unlikely, unless there is a common cause.
So, the thunderstorm hypothesis made sense.
3. BUT! If a power issue had damaged my gain modules, why did swapping to the NOS replacement modules not fix the problem?
4. ALSO! Why does the amp work normally sometimes, have DC on the output at others and do not work at all the rest of the time, with my original and NOS gain modules?
Now, the preamp has an external regulated power supply. The power supply is designed as 2 identical power supplies (+/- 21V and +9V), to power both the preamp (which I have) and the optional phono preamp (which I do not have). At the rear of the power supply enclosure are 4 identical outputs, 2 for power supply A, 2 for power supply B. Because I only connect my preamp, only 1 of the outputs is used. After changing the gain modules (for which the enclosure needs to be removed and opened), the umbilical cable would have been inserted to any of the 4 outputs. Was there an intermittent problem with one (or both) of the power supplies, perhaps due to parts degradation?
Also, both channels share the same power supply. A problem in the power supply would affect both channels!
The best thing to do would of course be to thoroughly test the power supply output, unloaded and under load, and see if the output is stable. Unfortunately that is not an easy option for me at the moment. Recapping may be an easy fix.
I am looking for the datasheet of the original electrolytic capacitors used in a Rowland Consummate preamp. Due to the age of the preamp (nearly 30 years) I want to replace the electrolytics. I would like to look up the specs of the originals before deciding what to replace them with.
There are 3 different types:
4 x 1000uF/25V marked IC LBAM M85{degree}C 2K07A
12 x 6800uF/35V marked Marcon AWF-M20 +85{degree}C 3B08A
6 x 100uF/63V marked IC RMRM B105{degree}C 22
Thanks,
Albert
PS Long read, below.
I have an old (1992/93) Rowland Consummate preamp that I have used for >20 years. A few years ago it developed a problem (DC on output of both channels). I contacted Rowland and they suspected a fault in the gain modules. Living in Australia, sending the unit to Rowland was not an option. Subsequently the diagnosis was done by email. No new gain modules were available and I put my preamp into storage.
A year or so later I was able to buy replacement NOS gain modules from Rowland. After installing them I had no sound at all. Swapping to my own (defective?) gain modules resulted in a working preamp, for a while. Then the dreaded DC on output was back. This was getting weird!
A few things are worth mentioning:
1. The problem started after we had weeks of severe thunderstorms. I normally switch the equipment off during storms, but may have been too late during the last one.
This originally led me to think about possible spikes or other mains power issues during the storms. I live in a rural area, we have overhead power lines and power failures are common during storms.
Could the storm have killed both my gain modules?
2. According to Rowland, it is rare for a gain module to develop a problem. To have 2 gain modules develop the same problem at the same time seems very unlikely, unless there is a common cause.
So, the thunderstorm hypothesis made sense.
3. BUT! If a power issue had damaged my gain modules, why did swapping to the NOS replacement modules not fix the problem?
4. ALSO! Why does the amp work normally sometimes, have DC on the output at others and do not work at all the rest of the time, with my original and NOS gain modules?
Now, the preamp has an external regulated power supply. The power supply is designed as 2 identical power supplies (+/- 21V and +9V), to power both the preamp (which I have) and the optional phono preamp (which I do not have). At the rear of the power supply enclosure are 4 identical outputs, 2 for power supply A, 2 for power supply B. Because I only connect my preamp, only 1 of the outputs is used. After changing the gain modules (for which the enclosure needs to be removed and opened), the umbilical cable would have been inserted to any of the 4 outputs. Was there an intermittent problem with one (or both) of the power supplies, perhaps due to parts degradation?
Also, both channels share the same power supply. A problem in the power supply would affect both channels!
The best thing to do would of course be to thoroughly test the power supply output, unloaded and under load, and see if the output is stable. Unfortunately that is not an easy option for me at the moment. Recapping may be an easy fix.
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