ARCHIVED FORUM -- March 2012 to February 2022READ ONLY FORUM
This is the second Archived Forum which was active between 1st March 2012 and 23rd February 2022
Piaf: I don’t know if your power company offers such a service, but if they do I recommend it with all my heart! Electrical contractors might also be a source for such protection.
I don’t know if your power company offers such a service, but if they do I recommend it with all my heart! Electrical contractors might also be a source for such protection.
valve1: Piaf: I don’t know if your power company offers such a service, but if they do I recommend it with all my heart! Electrical contractors might also be a source for such protection. I asked about such protection for my place in France, the hardware was 1000ish euro plus fitting. But best plan for lightening is plug everything sensitive out.
That's what I always do. Unplug. Being an electrician myself, I still do that!
Jacques
Unplugging everything is a sure bet, but there is an easier method.
The same surge protector/battery backup units available for our computers serve as a marvelous substitute for the whole-house protection.
And you can have music when the power goes out…. a silly benefit, but it works. I had that happen when I lived in Redmond, Washington and the whole neighborhood was blacked out. It was about 9:00 in the evening, so when the power went out, the house was pitch black but the stereo was still playing.
A surreal moment to be sure….. the bottom line though, the stereo was protected.
Jeff
Beogram 4000, Beogram 4002, Beogram 4004, Beogram 8000, Beogram 8002, Beogram 1602. Beogram 4500 CD player, B&O CDX player, Beocord 4500, Beocord 5000 T4716, Beocord 5000 T4716, Beocord 5000 T4716, Beocord 8004, Beocord 9000, Beomaster 1000, Beomaster 1600, Beomaster 2400.2, Beomaster 2400.2, Beomaster 4400, Beomaster 4500, Beolab 5000, Beomaster 5000, BeoCenter 9000. BeoSound Century, S-45.2, S-45.2, S-75, S-75, M-75, M-100, MC 120.2 speakers; B&O Illuminated Sign (with crown & red logo). B&O grey & black Illuminated Sign, B&O black Plexiglas dealer sign, B&O ash tray, B&O (Orrefors) dealer award vase, B&O Beotime Clock. Navy blue B&O baseball cap, B&O T-shirt X2, B&O black ball point pen, B&O Retail Management Binder
Back to the thread.
I have now new C1/238 in, I have correct showing 0.18 Ohm resistors in , the temp on TR2 are now down to 65*C, I put the plastic piece under the main switch back where it belongs.
But I cant adjust idle current, it 4-5 mV left channel and 3-4 mV right channel, non of the output transistors get hot, and I have correct voltage coming to and from them, I have checked all diodes and transistors on PCB, apparently they all check good.
So help and another thinkbox turn is needed.
I have sound and all controls and lamps are working.
Collecting Vintage B&O is not a hobby, its a lifestyle.
Boy oh boy Søren,You are having almost as much fun as I had with my BM6000 last year. All the same, I wish I had time to work on a project. I might have to wait until Christmas to get back on the bench. At least I can enjoy watching your project. Keep hanging in there.-sonavor
Check all resistors related to the idle current, around the trimmer etc.If, at some point, the idle current ran astray, one of the resistors could easily have an internal scar, not visible from the outside.Typically resulting in a far too high ohmic value or even an open connection.
Still no luck, check the constant current generator at the "bottom" of the circuit. If the current flow through the trimmer and relatedcircuit is wrong, the idle current will be off.
Martin
Thank you Martin, I´m into some work next couple of days, will be on it asap
Should I continue worrying about the temp, 65°C on TR2 ??
I don't remember how hot that transistor normally runs but generally I don't think I wouldworry too much about 65C.
Went through al Resistors from R152 to R186 PCB5, right and left channel, none shows more than 10 % of and right and left nearly the same, except R169 and R170, totally of but same value right and left.
I have correct 15V, 2 x 24V, 35V+, 35V-, only a little of is 33V shows at start up 31.2/3 but after 5 min at 32.5,
I´m not sure if I understand this right, the constant current generator is that the one with 4TR1? I have the 35V in and after 5 min 32.5V out.
At the output TRs I have left +1.0V -1.0, +21V -21V, +35V -35V right +1.1 -1.1, +21V -21V, +35V -35V. there are small variations max 0.2V but the receiver was not warm when measuring.
At the Emitter of TR112 and 113 I have -6.5V same on 212/3.
Had to stop to help Rich, but I´m going blind anyway staring at the drawings
Hi Søren,
I know that you are really in the thick of things with your Beomaster 4400 project, but perhaps you wouldn’t mind a break for a non-serious question.
Did you ever get around to finding an Il Divo CD? And if you did, did you like them?
Back to your TR112.
Piaf:Did you ever get around to finding an Il Divo CD? And if you did, did you like them?
I ordered the ILdivo CD with a visitor from the US, didn´t work, I ordered now with a friend of mine who goes to the music shop frequently, but I have heard them a couple of times now, and I do like them, and if the eggheads dont bring it, I will have to go myself and buy it.
Good Evening Søren,
Although I don’t know you on a personal basis, for reasons too complex explain, I am confident that you will find Il Divo extraordinary.
The selection of music, the execution, and the truly wonderful performers simply defy proper description.
Long day today, too much work for my like, will have to wait for the weekend before I get back to the 4400, I hope someone will post ideas or help.
Søren Mexico: Went through al Resistors from R152 to R186 PCB5, right and left channel, none shows more than 10 % of and right and left nearly the same, except R169 and R170, totally of but same value right and left. I have correct 15V, 2 x 24V, 35V+, 35V-, only a little of is 33V shows at start up 31.2/3 but after 5 min at 32.5, I´m not sure if I understand this right, the constant current generator is that the one with 4TR1? I have the 35V in and after 5 min 32.5V out. At the output TRs I have left +1.0V -1.0, +21V -21V, +35V -35V right +1.1 -1.1, +21V -21V, +35V -35V. there are small variations max 0.2V but the receiver was not warm when measuring. At the Emitter of TR112 and 113 I have -6.5V same on 212/3. Had to stop to help Rich, but I´m going blind anyway staring at the drawings
Well, clearly something is not right.Are you sure about the voltage on the 5TR112/113 emitters ? Check their base voltages. Normally, it should be around 0Vbut with an emitter voltage of -6,5V, a good 5TR113 should have around -5.8V on its base.If much closer to 0V replace 5TR113. If not check 5C138.
The constant current generator basically consists of the two transistors 0TR100 (on the cooling fin, compensating current for the actualoutput stage temp) and 5TR119. 5D102/103 also plays a role and so do 5TR114 (Hello 5TR112/113 emitters!) and 5TR120.
Keep up the good work.
I think we are getting near now, 5D102/103 shows OK measured cold on PCB, will go through the TRs and come back here.
Forgot to mention, all values are measured with FM on and volume "0"
At the moment I´m working on a 8 metric Ton printing machine, changing spare parts with a weight up to 150 Kg. In the evening I return to a small BM and fight 2 grams Transistors
Søren,
I still have Martin's Beomaster 4400 power amp kit so if Martin agrees it could be yours...
chartz: Søren, I still have Martin's Beomaster 4400 power amp kit so if Martin agrees it could be yours...
Thank you Jacques, good to know that help is available, and that Martin is helping out, but before I start changing anything I want to know why, it may be good fo all of us. Matins latest answer gives me something to work with, and I will continue my journey into this for me unknown country.
Dillen: Well, clearly something is not right.Are you sure about the voltage on the 5TR112/113 emitters ? Check their base voltages. Normally, it should be around 0Vbut with an emitter voltage of -6,5V, a good 5TR113 should have around -5.8V on its base.If much closer to 0V replace 5TR113. If not check 5C138. The constant current generator basically consists of the two transistors 0TR100 (on the cooling fin, compensating current for the actualoutput stage temp) and 5TR119. 5D102/103 also plays a role and so do 5TR114 (Hello 5TR112/113 emitters!) and 5TR120. Keep up the good work. Martin
Wanted to do as Martin told me, powered on and left to it to warm up, I turned my back to it for a few moments, and when I looked again the fault relay was drawn, powered of and started checking transistors and diodes, found 5D204 had gone bad, changed 5D104 and 204, powered on and the fault relay was triggered again. I'm going nuts here, heaven or Martin help me. Going to watch some football, and try again later.
Probably a DC on the output rail caused by one or more of thedriver- and/or output stage transistors.
Dillen: Probably a DC on the output rail caused by one or more of thedriver- and/or output stage transistors. Martin
I tested the output transistor and the transistors around there again with diode tester but all shows OK and same right and left
What I did not check was the C138-238
I am truly sorry for what you are going through, absolutely madding. Even if I had your remarkable electrical background and Danish training I could never, but NEVER do what you are doing…. I just don’t have the right temperament.
PLEASE understand that I fully understand that YOUR issues are 100 times anything I am facing, but I do have a favor to ask…. think of it as a brief diversion from the aggravation.
Since you are toiling over your Beomaster 4400 would you be so very kind as to check your FM socket to see if it is the same as your other Beomasters.
The one on my Beomaster 4400 looks similar to the others but is slightly smaller and even the adaptor provided with my FM antenna does not fit the socket.
In my case it is one of two things, either B&O had more than one size FM socket OR mine has the end of the FM antenna cleanly broken off in the socket preventing me for inserting the FM antenna plug. Before I start trying to get in there with pliers in an attempt to remove the unwanted piece, I’d sure like to know I was doing the right thing.
On a positive note since the FM antenna I found wouldn’t fit in the Beomaster 4400 I tried it on my BeoCenter 9000 and was BLOWN AWAY by the difference in reception. The volume increased and while I didn’t really notice the white noise before, it was there and disappeared with the FM antenna hocked up. Now I am bringing in KING-FM from Seattle, my favorite classical station as well as an oldies station…. the sixties and seventies are alive and well in Seattle.
Thank you kind sir and BEST wishes with your challenging Beomaster.
Søren Mexico: What I did not check was the C138-238
Yes gone again, changed them again and powered up and off again, did not trigger fault relay, Powered on and after 3-5 sec the relay was triggered.
This thing is driving me mad, I have been checking everything I can think of, next will be order all transistors and start with that, but that cannot be, I get the same values on all left and right with diode tester, no differences, I;ll give it a go with all the friggin resistors again, again and again. HELP
Piaf:Since you are toiling over your Beomaster 4400 would you be so very kind as to check your FM socket to see if it is the same as your other Beomasters.
Here goes. they look a little different but the measurements, of ground and center pin are the same, the adapter fits both.
BM 4400
BM 2400
Adapter fits in both
Thank you Søren so much! Especially for taking the time out of your time-consuming project, which is much appreciated! You are a Saint!
Apparently I don’t have anything stuck in there, so that is a good thing.
Mine is slightly different than your Beomaster 4400, but only slightly, it has 3 notches surrounding the center, kind of like the Mercedes-Benz emblem. And at this point, I am SO tired this evening that I wouldn’t even put money on my description, having I just looked at the FM socket.
I will take a fresh look tomorrow.
Can you take new pictures of the area(s) you are having problems with and post them? Have you gone through and re-soldered the related components and paths involved in the circuit you are having a problem with? A few months back I was having all sorts of problems getting an old Luxman amplifier (same vintage as the BM4400) working after a re-cap. I had hoped a quick cleaning and re-cap of the electrolytics would restore it but I ended up having issues with a hum in the signal path and I had a zener diode that didn't appear to work Replacing the zener by itself didn't fix the problem. I ended up going through and replacing all of the resistors and most of the capacitors. I kept all of the transistors and diodes (except that zener). In measuring the components I took out, they all measured pretty close to tolerances. So the main thing that exercise did was to re-solder all of the connections. I also reworked all of the connections of wires to and from the board. That amplifier now works great. That shotgun approach isn't always the way to go but every now an then you have to figure that the old audio device may have gone through some tough environmental tortures and requires a total rework. I'm not saying for sure that is your case but sometimes there are connection problems that are too hard to visually see. Also, while a lot of times diodes and transistors will fail - such that a DVM diode measurement can determine they are bad, there are also times when they fail under load but pass out of circuit. Of course the downsides of re-soldering everything is that you never know the specific error and it is a lot of work.Keep hanging in there,-sonavor
sonavor:Keep hanging in there,-sonavor
I will start again tomorrow, getting late here, will check a couple of things more and then come back here.
Just a resume before I start again, Friday the 4400 was playing, sound was there, but I could not adjust the idle current, Martin made some suggestions, which I wanted to try yesterday, To be sure that the receiver was warmed up, to find "warm failures" if any, I left it on for some 10 min. when I started measuring, I found that the fault relay was triggered, I checked that all the feeds was there, 24, 35 and 15V all there. As the manual says 5C138 and 238 has to be changed if DC was fed to the output stage, I checked these first, and yes they were bad, this has happened before, before I got the receiver, I had to change them together with all the Roe caps, So something went bad and I got DC on the board, before changing them again I went through diodes and transistors in the output stage, the transistors form 5TR113 onwards, tested on board with diode tester, shows OK right and left. the 0C100/200 as well.
The 01C100-103/200-203 OK. the only thing I found bad was 5D204, I changed D104/204. The receiver was now cold, without the PCB4 connected, I have to take it out when soldering on PCB5, I powered up and immediately turned off again, no problem, powered up again and after 3-5 sec. the fault relay was triggered again.
If I read the drawing right, the fault relay circuit is triggered from around 5TR116/117, 216/217, So today I will start searching there.
All this just to get my brain working in the right direction, it helps to write it down.
Was 5D204 shorted ?If so, I suggest you replace practically everything from 5TR215(incl.) outwards. Sorry.DC coupled amplifiers like this are not easy to dance with and components may measure fineon the bench and fail when power is applied due to internal scars from previous overloads.Even if you can make it play at some point, you will never know when an internally damagedcomponent somewhere gives up the ghost and starts a new avalanche.
I seem to remember that the safety circuit can be bypassed channelwise by lifting a resistor.Maybe this will allow you to measure around better. Of course, no speaker should be attached when there isa risk of DC on the output and it would be a good idea to feed the mains from a variac with a current meter.
Indeed, many repairshops would reject repairs like this based on the number of labour hours (let alone lack of skill).Of course, seeing as this is a hobby for us with noone counting hours, there's no reason to deem it out just yet.
5D204 shows MegaOhms in both direction, off board.
Most common failure mode of diodes is shorted but of course an open circuit can also happen.This means that the base connection of the next transistor stage has been left pretty much floating and uncontrolled.You can replace the diode but the big question is why it happened ? You get the idea...Replace the lot or you will never see the end of it.
Dillen: Was 5D204 shorted ?If so, I suggest you replace practically everything from 5TR215(incl.) outwards. Sorry.DC coupled amplifiers like this are not easy to dance with and components may measure fineon the bench and fail when power is applied due to internal scars from previous overloads.Even if you can make it play at some point, you will never know when an internally damagedcomponent somewhere gives up the ghost and starts a new avalanche. I seem to remember that the safety circuit can be bypassed channelwise by lifting a resistor.Maybe this will allow you to measure around better. Of course, no speaker should be attached when there isa risk of DC on the output and it would be a good idea to feed the mains from a variac with a current meter. Indeed, many repairshops would reject repairs like this based on the number of labour hours (let alone lack of skill).Of course, seeing as this is a hobby for us with noone counting hours, there's no reason to deem it out just yet. Martin
Thats bad news indeed Martin, I will try today to disconnect the relay channel wise, then at least I can see which channel (or both) is triggering it.
But I assume your are right, and will give this a long thinker, Its not that I give up on this one, but the costs coming to me. I hate doing half works without the proper tools, so at least a Variac is needed, then comes all the spares for both channels which I would do totally and not only from TR115 onwards.
Then to consider is, if I make failures changing parts and/or soldering, which I'm sure will occur, we are talking about some 300 solder points, and then there may come other failures in the rest of the unit.
On the other hand I know I will be thinking about this unit for a long time if I give up, and always regret giving up. So after checking a little more today I will go into the think box for a couple of days.
And I do still have Martin's kit ready to ship to you if he's okay, don't forget.
chartz: And I do still have Martin's kit ready to ship to you if he's okay, don't forget.
What is included in the kit Jacques ??
Well everything for one channel.
About little problems that are annoying, I have this CDX door which opened sometimes and most of the times I had to help it. This had been the case for months, in spite of a new belt from Martin. Then the other day it simply refused to open. For good. Last night I had a dream and I fixed it. Today I just did what the dream told me. Well I changed the motor (I have a scrap CD3300, I only had to change pulleys) and guess what it worked!
That 4400 of yours WILL work!
chartz:Well everything for one channel.
Thank you Jacques.
@ Martin, can you provide kit for both channels ??? mail me and price to Horsens if yes. I just cant give up here, I'm running around in circles, making my wife crazy too.
Absolutely fine with me.This kit was put together exactly for situations like this.Jacques' kit may be an early revision and I don't remember if it has been updated since or not but you caneasily compare it to what you have in your Beomaster and work from there.It's a complete output channel from 5TR112 (5TR212) outwards.
Dillen: chartz: And I do still have Martin's kit ready to ship to you if he's okay, don't forget. Absolutely fine with me.This kit was put together exactly for situations like this.Jacques' kit may be an early revision and I don't remember if it has been updated since or not but you caneasily compare it to what you have in your Beomaster and work from there.It's a complete output channel from 5TR112 (5TR212) outwards. Martin
Martin: Can you provide one more kit ???
Jacques: As you see Martin, as always helpful, agree to let me have it, will be back with you shortly.
Søren Mexico: Martin: Can you provide one more kit ???
Sure.Amplifier kits exist for many of the "larger" Beomasters and some Beocenters for convenience (I usethem myself occasionally) but will you need more than one kit ?
Dillen: Søren Mexico: Martin: Can you provide one more kit ??? Sure.Amplifier kits exist for many of the "larger" Beomasters and some Beocenters for convenience (I usethem myself occasionally) but will you need more than one kit ? Martin Not if its for both channels, but Jacques mentioned its for one channel
Not if its for both channels, but Jacques mentioned its for one channel