Beomaster 1001 , how can I take it apart ?

34 replies
FR
Offline
Frankenberg
Bronze
Posted March 13, 2019 at 07:43 GMT
#2119954

ok, FM ZF could not translate google correctly😧

This means the IF of 10.7 MHz

The Zehnerdiode in the power supply to the 100k tuning pots but is also very important, it determines the tuning range of the FM tuner, the voltage is not correct here and constantly the tuning range is too high or too low, meaning you can then only stations below 88MHz or received above 108MHz!

 

I noticed there is a note in a service manual Beomaster 1200, there is a modification for the FM area.

in some older devices, no 3.3k resistor was connected in parallel with the STEREO lamp!

If the bulb had blown, it came to the deteriorated and distorted FM playback, up to the failure of FM!

do you have maybe a device from this old series in front of you?

 Then you should check if the STEREO lamp is ok!

No joke I tested it on one of my Beomaster1200 without this 3,3k resistor parallel to the lamp, without the bulb there is no FM reception!

 

Incidentally, I also have a small problem with the STEREO display on the BM 1001; if I switch to TAPE or PHONO the lamp does not turn on, is that the same with yours? On a BM1200 it lights up!

S(
Offline
sebalele (archived2)
Bronze
Posted March 13, 2019 at 09:52 GMT
#2119955

W.Frankenberg wrote:

This means the IF of 10.7 MHz

The Zehnerdiode in the power supply to the 100k tuning pots but is also very important, it determines the tuning range of the FM tuner, the voltage is not correct here and constantly the tuning range is too high or too low, meaning you can then only stations below 88MHz or received above 108MHz!

OK , this is usefull ; I can not check till Sunday but seem as you said . I should  check on R47 (47K) if there any variations tuning throught P1-3 or FM .

I think that is just an open contact or something like .

W.Frankenberg wrote:

I noticed there is a note in a service manual Beomaster 1200, there is a modification for the FM area.

in some older devices, no 3.3k resistor was connected in parallel with the STEREO lamp!

If the bulb had blown, it came to the deteriorated and distorted FM playback, up to the failure of FM!

do you have maybe a device from this old series in front of you?

 Then you should check if the STEREO lamp is ok!

No joke I tested it on one of my Beomaster1200 without this 3,3k resistor parallel to the lamp, without the bulb there is no FM reception!

 

Somewhere I read something about it , now try google for this retrofit

I can not say this is an early version but it's sure related to service manual . 

At first check 2 lamps were ok ( i don't remeber stereo...fm) but it sounded and received fine .Using just a 300ohm dipole .

I'm going to check for stereo bulb and resistor 

W.Frankenberg wrote:
Incidentally, I also have a small problem with the STEREO display on the BM 1001; if I switch to TAPE or PHONO the lamp does not turn on, is that the same with yours? On a BM1200 it lights up!

Now I'm confused , I give a try . Sure that in FM stereo , if I push mono both bulb (mono&stereo ) lite but sound mono . I don't remember with tape/phono . I'll check

Ciao 

Gabriele

S(
Offline
sebalele (archived2)
Bronze
Posted March 13, 2019 at 10:04 GMT
#2119956

I'm not in my cave now but looking at the schematic , appear to be ok having both stereo and mono lite when in fm mode with station in stereo and mono pressed but (right) it sound mono .

Otherwise is strange having stereo light ON when you use tape/phono selector .

In this case fm module should not be supplied and so the stereo light .

I have to test to confirm . But should works so , don't you find it ?

 

Gabriele

S(
Offline
sebalele (archived2)
Bronze
Posted March 13, 2019 at 10:04 GMT
#2119957

I'm not in my cave now but looking at the schematic , appear to be ok having both stereo and mono lite when in fm mode with station in stereo and mono pressed but (right) it sound mono .

Otherwise is strange having stereo light ON when you use tape/phono selector .

In this case fm module should not be supplied and so the stereo light .

I have to test to confirm . But should works so , don't you find it ?

 

Gabriele

FR
Offline
Frankenberg
Bronze
Posted March 13, 2019 at 10:24 GMT
#2119958

The diagram shows three lamps from the left :   FM, MONO and POWER (not STEREO !!)!

The STEREO lamp can be seen below in the diagram, it is switched by the TR16!

The FM lamp is power by TR12 and the brightness can be adjust by R157!

The power lamp should be on if power is on, every time!

The mono lamp is on when the mono switch push and give ground to the lamp !

 

S(
Offline
sebalele (archived2)
Bronze
Posted March 13, 2019 at 11:58 GMT
#2119959

W.Frankenberg wrote:
The diagram shows three lamps from the left :   FM, MONO and POWER (not STEREO !!)!

Right !

R265 should be 3K3 you said before 

So, stereo lamp should goes off when tape/phono are selected cause there no power on FM module input .

W.Frankenberg wrote:

The power lamp should be on if power is on, every time!

The mono lamp is on when the mono switch push and give ground to the lamp !

ja , power lamp take direct from power supply and switch 35 take R168 to ground 

Clear , hope this evening  can give some test .

Ciao

S(
Offline
sebalele (archived2)
Bronze
Posted March 20, 2019 at 21:14 GMT
#2119960

Well,

I get back from some days outdoor , I thought to follow the fault/signal  by scope .

So I put probe on FM module to look for signal on test point ..... and these are present !

I plug an headphone and ...voilà ! Music!

Hum , I'm a little disappoint . This sort of problems usually are fake contact , cold solder ,switch and often they get back.

I've punished hard the switches , bet the pcb with screwdriver and the B&O never give up to sing .

I'll let play for some days then I have to restore the wood around the Beomaster .One side is missing ; I have to play with wood .

Some details to come .

Gabriele

 

 

S(
Offline
sebalele (archived2)
Bronze
Posted March 20, 2019 at 21:48 GMT
#2119961

W.Frankenberg wrote:
Incidentally, I also have a small problem with the STEREO display on the BM 1001; if I switch to TAPE or PHONO the lamp does not turn on, is that the same with yours? On a BM1200 it lights up!

 

Stereo lamp goes off when tape or phono are selected .

FR
Offline
Frankenberg
Bronze
Posted March 20, 2019 at 22:21 GMT
#2119962

Hello Gabriele

 It is really stupid when an error is suddenly gone and is not clear what the cause was!

Thanks for the information about the behavior of the STEREO lamp when you switch to tape or phono, the Beomaster 1200, in many parts identically constructed, behaves quite differently, more logical as I mean, he turns on the lamp when tape or phono pressed is!

If that is so I have one less problem with my Beomaster 1001!

I wish a lot of fun with the woodwork.

S(
Offline
sebalele (archived2)
Bronze
Posted March 27, 2019 at 20:13 GMT
#2119963

 

Ciao ,

some wood working has been done , 

not easy to take off the frame from the BM1001 . I think they're fitted before the electronic and pcb .

Anyway , pull carefully , some little clip come frm the wood .

I miss one side . I bought a strip of wood and cut like other side

Now need to be painted

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