[alf]

Hi All,

just a quick update:

I have the 15.5VDC at 2R172 and 14.9VDC at 2R171 but I can not see the 12VDC at the crosspoint of emitter of 2TR38 and collector of 2TR37.

i checked TR37 and installed a jumper from C of 2TR37 to P16-4 thanks to a broken track.

But there are still no 12VDC at 2P16-4, hence no supply of 12VDC for the capstan motor ??

at the moment I am turning in circles….progress but no progress ?

any comments or pointers ?

ALF

 

 

[alf]

Thank you Die and Nick for your inputs – this is where I am at:

i checked 2TR17 which is fed with a 5 VDC supply which tested ok – then checked TR3 on the display board which tested ok.

suddenly the drawer motor came back on board and so did the display…..seems totally unrelated to me but…no complains.

then I checked the belt was fitted correctly and not running on the edge of the black flywheel – belt was sitting perfectly….and NO, the belt is fairly new.

and again: when play is activated the display comes on for a moment, I can hear what has to be the clicking of the solenoides of the tape drive but it just wont play !!

When unsoldering 2P16 I lost the soldering eye of pin1 which is connected to ground – so is Pin5. In that case I connected those two pins. (I blame the desoldering gun)

looks like I still have to find the cause of the not firing tape drive.
One thought was on those two grey wires which connect to the capstan motor terminals A and B.

obviously there were two options of making the connection, so I tries both without any impact on the issue at hand.

any help is most appreciated – thank you

ALF

 

[alf]

I did get back to follow up your suggestion:

all resistors on the PSU section have been tested and all tested ok.

to my understanding the PSU section supplies the necessary voltages to board #2 but

the display is still dead, the drawer motor does not engage nor does the tape drive although when the mains is switched on I can hear a short click in the drive , as it would try  to engage ?…..that’s it.

I feel the 4.6VDC is not enough to light up the display and it puzzles me why and where the lack of voltage is happening ?

will get over it once more – not overly optimistic about a good outcome though.

ALF

 

 

[alf]

Thank you for the  pointers – I thought I did check but will revisit the PSU section.

It seems odd though I can measure  the 5VDC, 15VDC and 26VDC supplies on P2 & P3

ALf

[alf]

Hi All,

beoparts shop was so kind and sent a replacement idler wheel which arrived yesterday.

It is now installed and that knocking issue has disappeared – great outcome.

thanks again to Martin who pointed out a possible wheel problem.

records are playing as we speak….off to the next project.

regards, ALF

 

[alf]

Thank you Martin – I have contacted the Beoparts shop.

it is indeed not easy to see any faults on that wheel with the naked eye.

lets wait and see what comes out of it….

regards

ALF

[alf]

Hi Chris,

good points which I thought I had covered but will certainly have another look !!

I am aware that tiny felt pad can not be too thick as it would otherwise act as a

break pad.

once the workbench is free again I shall have another go and will report back as usual.

regards

ALF

[alf]

Hi Chris,

many thanks for your reply….sounds like I have done everything correctly ?!?

yes, the newly designed idler came from Beoparts, not ebay !

you are right, that little felt tip of the brass tongue is missing – I had ordered a replacement….but fitting that tiny thing turned out to be unsuccessful, instead I used some similar material. That should not cause the issue I would think.

yes again, the new belt came from Beoparts ?

sounds like I have to get back to the 1203 and do some further searching…..but I am running out of ideas…..so, keep them coming please.

regards

ALF

[alf]

Thanks Filip,

my thoughts precisely – nice to see the carriage moving correctly again.

always interesting how many challenges this table can throw at you……

ALF

[alf]

Hello Christian,

thank you for your reply – very sorry to say you just missed out on a 10/10,

But a  9/10 for inspiration isn’t too bad either I thought ?!

I did check that 1cm track under the magnifier, than clean that short track with a fiber glass pen as well and still did not see any damage…..which sidetracked me.

assuming that there may be a wire issue further on stopped me for now but thanks to

you I simply connected a short wire jumper between SI and C of 1TR20…..success ??

and now the platter starts at 33rpm as it should.

many thanks again ?

ALF

 

 

[alf]

Tested the mentioned transistors – off board ! – and both tested fine.

obviously one other (or more) component(s) is faulty as this issue was not a gradual decline but appeared suddenly.

at this stage I want to rule out a contact issue as the table performs normal once the carriage has moved in via FE to its drop-down point.

ALF

 

[alf]

Thank you for your input, I will test those two transistors.

just a brief recap:

i verified 6V at The C of  1TR20, but when measuring the SI on the mainboard the max I see is 2V ?

i assume this is the signal 3IC4 is receiving ?
it seems the logic has locked-in the 45rpm as the platter starts only with 45 when ON is activated.

the components of the SI circuit are working ! The. Platter motor adjustment is another matter but should not interfere with the start-up of the carriage, moving in !

i hope my explanation didn’t lead to misunderstandings here.

any help is most welcome ?

ALF

[alf]

Hi,

i revisited the adjustment of the platter motor as the table seem to have 45rpm locked in ?

yes, I can operate a speed change manually, but….

adjusting the motor as per SM I set all trimmers – 4VR1/2, 1VR1/2/3 – in their center position.

I can adjust the corresponding  33rpm voltage at about 15V at 42Hz, 45rpm at about

15V at 53Hz – not 59Hz as the training manual suggests.

checking the SI signal I should see 6V after a 10ms delay…..what I am getting though

is just under 2V which is obviously far too low……but why ????

6V are present at the suppy, 1TR20 measures fine 1C15 is 10uF / 16V – no 6V cap at hand.

the 24V supply is on the low side at about 23.4V ?!

would really appreciate some input

thanks guys

ALf

 

[alf]

Hi Christian,

refer to the service manual page 5-7 explosion drawing:

remove motor from the turntable by unscrewing from its 3 anker points and disconnect.

take off idler wheel (one thing less to worry about)

take off the cover – item 184

separate stator from the motor – item 177

remove motor bracket, held in position by 3 rods and secured by one nut – item 164

that frees up the rotor and its bottom bearing – item 178

remove and replace bearing with its oil-soaked felt ring after cleaning.

hope that gave some idea how to remove the bottom bearing

ALF

 

[alf]

I guess it would have been tricky to explain……the good news is: i worked it out myself.

isn’t that nice ?! ???

ALF

[alf]

Hi Craig,

adjusting 1VR3 in combination with fine adjusting the 33 & 45 trimmers dud the trick.

if you listen to the motor noise you get a good feel when its right.

and thank you Martin, I feared there was more serious stuff to investigate…..

its back to working order ??

ALF

 

[alf]

Thanks Martin & Christian fir replying.

Yes, with the “finger-test” I can feel the motor vibrating but not spinning at 45rpm.

Question is what course of action I have to engage with ?

ALF

[alf]

thanks Tim,

exactly the guy I was after ?

contact has been established !

ALF

[alf]

Thank you so much for letting me know – that is good news ???

enjoy – regards, ALF

[alf]

I did replace 1D20 as it tested very different from a new ZDP one.

the uP supply is 5.12 VDC at P6-1 which would allow a tolerance of 2.5% for the regulator.

still, no StBy dot present. I “reinforced” the pressure of the two flat connectors that plug into the P6 connector to make sure there is proper contact.

i am sure some of you have been at a dead-end and that is where I am at the moment.

no issues found yet with missing continuity, the DC voltage after the rectifier looks normal and yet no StBy dot, meaning no turn-on possible.

yes, I had very briefly the StBy dot and the -/+15 supply but something must have died? Lets hope it is not the uP.

Without turning on the BG I won’t get any reference voltages (except the 5V line) which may point to other problems ?!

it might be best to shelf the BG again to “free my mind” and start again some other time.

thank you all who have been on board with pointers and suggestions, very much appreciated.

ALF

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