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Topic: Beauleiu 708 el stereo NO SOUND?????
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Phil Murat
Jedi Master Film Handler
Posts: 671
From: Villeneuve St Georges, France
Registered: Dec 2015
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posted November 30, 2018 12:53 AM
Hello Mark,
A) I suggest you these electrical measures :
- If Voltage recorded is +32v instead of 24V (small tab below picture) , try to adjust with RA2 Trimmer. If no change is observed, means Voltage Regulator IC1 (L200C, 5 lugs) has failed out , or closed capacitor (green bloc) has failed as well.
If Voltage recorded is 0v instead of 24V, measure IC1 (L200C) incomming voltage from Diode D5 last pin : you should read +32V.
If voltage is very low and fuse is OK, means Diodes "train" D1 to D5 has to be reniewed.
Before to measure "24V" on the tab, disconnect the Red Lug from this tab ; just in case there is a 32V (No more regulated Voltage). A +32V could stress some Pre-Amp components .
L200C Power Regulator , Diodes, Caps are easy to find on the market for few money.
- You should find +42V on upper lug (Upper side of the picture).
This voltage is usually stable but not regulated. It supplies current for Amp Power section.
B) Are both fuses Ok ?
Let us know.
Hope this will be helpfull
Phil
[ November 30, 2018, 02:39 AM: Message edited by: Phil Murat ]
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Phil Murat
Jedi Master Film Handler
Posts: 671
From: Villeneuve St Georges, France
Registered: Dec 2015
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posted December 05, 2018 12:44 AM
Hi Mark,
Yes, it does..... for 100%
Brown wire is the 24v power for pre-amp section .
The small lug soldered on board is broken , flush to the board, remaining portion of lug is still inside spade connector.
You need to replace the lug on the board.
This is a usual failure on Beaulieu 708, minor, fortunately .......
You need to remove the regulating board to perform the job.
The lug is fitted on the left corner of board, next to green capacitor.
You can see this lug on first picture (post above) , a red arrow +24v is pointing it.
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Phil Murat
Jedi Master Film Handler
Posts: 671
From: Villeneuve St Georges, France
Registered: Dec 2015
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posted December 05, 2018 05:48 AM
Hi Mark,
Absolutely , see through a close picture :
This kind of connector is unfortunately very fragile......
If you want to obtain configuration as origine , you need this kind of lug (2,8mm) :
An alternative solution is to solder a wire portion on board with this kind of male connector :
Alternative solution is my prefered because when you need to disconnect the spade connector from the pin , there is no stress on the solder on the board.
Do you have necessary tools to make the job ?
- A small soldering iron maxi 20w, "pencil tip"
- Soldering wire , diam 1mm approx, electronic quality.
- A lengh portion of copper mesh, approx 10cm (used for remove former soldering material on board track on pin lug location)
- Heat-Shrinkable sleeve, tube (red colour)
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Phil Murat
Jedi Master Film Handler
Posts: 671
From: Villeneuve St Georges, France
Registered: Dec 2015
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posted December 05, 2018 06:08 AM
The 2,8mm lug connector is fitted in its own hole , close to the capacitor.
Hole is 0,8mm to 1mm approx diameter , so far I remember.
IMPORTANT NOTICE FOR BOARD REMOVAL/INSTALATION :
1)Observe Power regulator (in the midle) which is fitted to casing.
This regulator BD646 HAS TO BE PERFECTLY INSULATED FROM THE CASE.
The Regulator lug is installed on a micas sheet and a tiny plastic bushing on 3mm screw.
When re installing BD646 lug , check insulation with Ohmeter between BD646 lug and case , resistance has to be very very high !!!
Check final Electrical resistance between lugs and case once board installed and before to power on the machine
A poor insulation will result in BD646 immediate failure and will cause main motor no more regulated.
2) For installation of L200C power regulators , this is opposite to 1): Resistance between their lugs and case HAS TO BE VERY LOW (almost perfect continuity).
If this condition is not met you will experienced extra spurious noises when playing sound.
For L200C installation, no insulating bushing, no micas sheet below lug......
You can see the plastic bushing and micas sheet (Midle BD646 Regulator) on the picture , upper post...
Do not hesitate to ask for more info if there is something confused.
Let us know
Phil
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Mark L Barton
Jedi Master Film Handler
Posts: 621
From: Bristol, South Glos, England
Registered: Mar 2009
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posted December 05, 2018 04:07 PM
SUCCESS!!!!!!!!!
Hi Phil, thanks to you I now have a Beaulieu 708el Stereo projector that is playing back sound. The brown blade I could see where it was attached, whilst doing the repair the black cable lug to the amp simply fell off (design fault, too much stress??) So, instead of finding lugs to solder into the circuit board, I used audio cable and attached the remainder of the lug to the cable, then reattached to the black and brown wires. This way there is slightly less stress on the solder etc etc. So Phil, thank you , Merci bien. PS I now need to find a new drive belt for the flywheel that goes to the little motor next to the audio circuit board, as its very loose and causing the projector to wow and flutter. Where would be the best place to get that belt?
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