First troubleshooting and solving defects. Then measurements and testing. Only after that any changes in the device.
No need to measure ESR of the old stuff. They are so bad that values are way off. Quality was so so anyway. Can be done with a DMM. Meanwhile they are so old that replacing is almost mandatory 😉
As said, take extra care to replace small value electrolytic input caps till 10 uF for MKS film caps and larger output caps for bipolar electrolytic caps. I forgot why but there is a reason for it, probably a few Volt offset!?! Also make sure to create distance between hot transistors and electrolytic caps.
If you want longevity and very good results this device asks for carefully thinking/planning.
No need to measure ESR of the old stuff. They are so bad that values are way off. Quality was so so anyway. Can be done with a DMM. Meanwhile they are so old that replacing is almost mandatory 😉
As said, take extra care to replace small value electrolytic input caps till 10 uF for MKS film caps and larger output caps for bipolar electrolytic caps. I forgot why but there is a reason for it, probably a few Volt offset!?! Also make sure to create distance between hot transistors and electrolytic caps.
If you want longevity and very good results this device asks for carefully thinking/planning.
Last edited:
No that is not my intent, as I want to take some sample measurements of ESR at 10k and 100kHz for comparison, and to check capacitance and leakage.
Hi!
Here is another Proton 1100 blown up after years of doing en excellent job! Is there still a chance to send me the schematic?
I would be very grateful. How does this PM system work without posting my email here?
Thanks a lot
Ekkihoffmann
Here is another Proton 1100 blown up after years of doing en excellent job! Is there still a chance to send me the schematic?
I would be very grateful. How does this PM system work without posting my email here?
Thanks a lot
Ekkihoffmann
You simply request that interested members send you a PM or initiate one yourself. You can reply to the PMs or send one after a moderated period of time has elapsed, by selecting "user CP" from the menu bar and going to private mail and following the prompts. The whole exchange is private and keeps the thread focused on the topic. Well, that's the intent at least.
Last edited:
Click on the name of the person you want to contact privately. The drop-down menu includes "Send a private message to {person}"
One possible glitch. "New members" are restricted until management sees they are not making trouble/spam. You have been a member for years but only one public post.
Attachments
My 1100 has been dormant for many years. As is, it came up fine on a variac. It is a later version than the Service Manual, with a few changes already identified.
The raw DC rails are +/-42V (compared to 36V), which has no consequence except that the regulator heatsinks are noticeably hot, so I will think about augmenting them a bit.
The MM section of the phono stage is simplified, with a different opamp (M5219L instead of NJM2037) and just one opamp in the M5219L is used. The opamp is configured with the 2SK240 as per the 2nd high S/N app circuit in the M5219L datasheet. One channel had negligible output offset, and the other had 10mV offset so no problem there, and no need for a trimpot.
The M5219L has a lower rail max limit, so the dropping resistor for rails E and F is now 220R and the rails sit at +/-22V.
Interestingly the phono stage uses Nichicon MUSE series electrolytics, with everything else by TEAPO.
The main vol control is an ALPS unit which appears to be something like an RK27 series rotary.
So onwards with the job.
The raw DC rails are +/-42V (compared to 36V), which has no consequence except that the regulator heatsinks are noticeably hot, so I will think about augmenting them a bit.
The MM section of the phono stage is simplified, with a different opamp (M5219L instead of NJM2037) and just one opamp in the M5219L is used. The opamp is configured with the 2SK240 as per the 2nd high S/N app circuit in the M5219L datasheet. One channel had negligible output offset, and the other had 10mV offset so no problem there, and no need for a trimpot.
The M5219L has a lower rail max limit, so the dropping resistor for rails E and F is now 220R and the rails sit at +/-22V.
Interestingly the phono stage uses Nichicon MUSE series electrolytics, with everything else by TEAPO.
The main vol control is an ALPS unit which appears to be something like an RK27 series rotary.
So onwards with the job.
Teapo -> replace them all. Higher raw DC voltage does have consequences as things go even hotter. Better solve a problem at the root, is there a way to have lower raw DC voltages?
Lower raw voltage?
One way would be the changing of the mains transformer , mine has 2x30V ac!
And this could solve another problem: the built in transformer has a pretty strong magnetic field , in my setup it induced hum in an equaliser over a distance from f 30 cm! I think, a toroidal transformer with 2x 25V would be a good solution!
My proton seems to have one output stage blown!
One way would be the changing of the mains transformer , mine has 2x30V ac!
And this could solve another problem: the built in transformer has a pretty strong magnetic field , in my setup it induced hum in an equaliser over a distance from f 30 cm! I think, a toroidal transformer with 2x 25V would be a good solution!
My proton seems to have one output stage blown!
This particular 1100 model is 220Vac rated. I have 240Vac, so the raw DC is going to be +10% for starters from nominal. The raw DC is only applied to two 50V rated filter caps, so as indicated, there are no consequences other than a slightly higher dissipation in the +/-30V regulator pass transistors, which I will address.
PS. If anyone has come across a service manual for a Proton AM-300 and can share then please PM me, as there has only been a schematic available on-line for the last decade.
PS. If anyone has come across a service manual for a Proton AM-300 and can share then please PM me, as there has only been a schematic available on-line for the last decade.
Last edited:
Actually raw DC will go up by 14%, if that is no problem for the filtering caps , ok! But take care, the 30V regulators have to burn about 40% more each at a 10% rise of the mains voltage!
The "no consequences" is said too easy. Please see suggestion of Ekkihoffmann.
If the stray field influences even other devices AND it is wound for 220V AND the device is burning energy for no purpose AND things become too hot then the suggestion to buy a 2 x 25V toroid or Rcore makes a lot of sense!
Last edited:
It's fine to suggest, but the assessment outcome is that there is no benefit to be gained, and it introduces a large risk in deploying an alternative transformer on many fronts, including the stray field topic.
The existing transformer appears to be nicely shielded already, and is located as far as practical away from circuitry, and I had already introduced an additional metal shield about a decade ago to constrain coupling from the mains voltage wiring as well as any leakage from the transformer.
The transformer primary current does not increase markedly from 220V to 240V, as expected of a transformer that has to be designed for +/-10% mains voltage tolerance.
The other two issues raised of burning energy, and parts becoming too hot, are not supported for this particular preamp.
There is nothing imho requiring a 'solution'.
The existing transformer appears to be nicely shielded already, and is located as far as practical away from circuitry, and I had already introduced an additional metal shield about a decade ago to constrain coupling from the mains voltage wiring as well as any leakage from the transformer.
The transformer primary current does not increase markedly from 220V to 240V, as expected of a transformer that has to be designed for +/-10% mains voltage tolerance.
The other two issues raised of burning energy, and parts becoming too hot, are not supported for this particular preamp.
There is nothing imho requiring a 'solution'.
Any chance of helping me, I'm about to buy signal lamp for my 1100, but still havent open it. Can someone pls check and find out what kind of signal lamp do i need?
There is a 6.3V 150mA bulb associated with the power switch in the parts list - the bulb is powered from its own 6Vac secondary winding.
https://www.dalmura.com.au/static/Proton%201100.pdf
https://www.dalmura.com.au/static/Proton%201100.pdf