Blaupunkt SQR 88 Woodstock not displaying a thing! - UK Vintage Radio Repair and Restoration Discussion Forum

DaniTDS · 28th Sep 2018, 4:42 pm

Hi!
I have three of these Blaupunkt SQR 88 Woodstock. I got one of them to work, but would like to repair one of the other two's.
The problem they have, as many others I saw on the internet, is that when you turn it on, the backlight works but the LCD displays nothing, but I can't tune orr enter a code. I can insert a tape and it starts spinning but can't rewind or anything, except taking it out (cassette is completely electromechanical).
Where should I start looking in?

Regards

paulsherwin · 28th Sep 2018, 4:47 pm

Is it locked to a particular vehicle VIN?

DaniTDS · 28th Sep 2018, 5:56 pm

Hi Paul,
I can't know. When powering up, it should display CAR and a VIN, and when pressing the rocker switch it should ask for a code, or activate itself if code protection is disabled. But the display shows nothing! So I can't do anything.

Regards

'LIVEWIRE?' · 28th Sep 2018, 6:49 pm

The Woodstock SQR88 almost certainly pre-dates the use of VIN locking. It will have a normal 4-digit security code. As to the lack of display - have you checked that both power lines are present (There will be a +12v Accessory supply, plus a permanent +12v line for memory back-up) In some radios the display is blank if the B.U. supply is missing. Other than that, it could be either a faulty display or faulty display driver circuitry.

DaniTDS · 28th Sep 2018, 7:00 pm

Hi LIVEWIRE, the Woodstock has 4 pins: 12V continuous, 12V ignition, aerial and mass. I plugged both 12V and mass. I tried the LCD from this unit on a working Woodstock with no problems.

Regards

Chris55000 · 1st Oct 2018, 1:00 am

Hi!

This almost certainly sounds like one of the internal voltage–regulators feeding the micro or one of the other subsidiary LT lines in the set has disappeared, and unfortunately tracing it ie going to be a matter of taking the set apart and peering at the pcbs I'm afraid!

However I can offer a small crumb of comfort, in as much the front–panel display and LCD controller is usually built on a separate panel of it's own in this type of set, so you should see 8 or so connections connecting it to the rest of the set, and one of these will be the micro's power–supply point!

Have a good peer at it and get back with good clear pictures if you're still stuck!

Chris Williams

DaniTDS · 1st Oct 2018, 12:28 pm

Hi Chris, thank you!

I'll try to get some photos. Almost all the circuitry is on the same PCB, except the final stage section which is a block you can take away (it has a fan!) and the front buttons. The LCD is connected to the main PCB through two flat multipin buses. The LCD controller is a PCF8576. About voltage regulators, at the start of the voltage input path there is a L4916 8.5V regulator I think, and a L498 which I cannot identify. Maybe I should start testing its output.

Regards

28th Sep 2018, 4:42 pm	#1
DaniTDS Diode Join Date: Jun 2016 Location: Pontevedra, Spain Posts: 8	Blaupunkt SQR 88 Woodstock not displaying a thing! Hi! I have three of these Blaupunkt SQR 88 Woodstock. I got one of them to work, but would like to repair one of the other two's. The problem they have, as many others I saw on the internet, is that when you turn it on, the backlight works but the LCD displays nothing, but I can't tune orr enter a code. I can insert a tape and it starts spinning but can't rewind or anything, except taking it out (cassette is completely electromechanical). Where should I start looking in? Regards Attached Thumbnails

28th Sep 2018, 4:47 pm	#2
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,945	Re: Blaupunkt SQR 88 Woodstock not displaying a thing! Is it locked to a particular vehicle VIN?

28th Sep 2018, 5:56 pm	#3
DaniTDS Diode Join Date: Jun 2016 Location: Pontevedra, Spain Posts: 8	Re: Blaupunkt SQR 88 Woodstock not displaying a thing! Hi Paul, I can't know. When powering up, it should display CAR and a VIN, and when pressing the rocker switch it should ask for a code, or activate itself if code protection is disabled. But the display shows nothing! So I can't do anything. Regards

28th Sep 2018, 6:49 pm	#4
'LIVEWIRE?' Rest in Peace Join Date: Mar 2006 Location: N.W. Oxfordshire(Chipping Norton) Posts: 7,306	Re: Blaupunkt SQR 88 Woodstock not displaying a thing! The Woodstock SQR88 almost certainly pre-dates the use of VIN locking. It will have a normal 4-digit security code. As to the lack of display - have you checked that both power lines are present (There will be a +12v Accessory supply, plus a permanent +12v line for memory back-up) In some radios the display is blank if the B.U. supply is missing. Other than that, it could be either a faulty display or faulty display driver circuitry.

28th Sep 2018, 7:00 pm	#5
DaniTDS Diode Join Date: Jun 2016 Location: Pontevedra, Spain Posts: 8	Re: Blaupunkt SQR 88 Woodstock not displaying a thing! Hi LIVEWIRE, the Woodstock has 4 pins: 12V continuous, 12V ignition, aerial and mass. I plugged both 12V and mass. I tried the LCD from this unit on a working Woodstock with no problems. Regards

1st Oct 2018, 1:00 am	#6
Chris55000 Nonode Join Date: Aug 2007 Location: Walsall Wood, Aldridge, Walsall, UK. Posts: 2,870	Re: Blaupunkt SQR 88 Woodstock not displaying a thing! Hi! This almost certainly sounds like one of the internal voltage–regulators feeding the micro or one of the other subsidiary LT lines in the set has disappeared, and unfortunately tracing it ie going to be a matter of taking the set apart and peering at the pcbs I'm afraid! However I can offer a small crumb of comfort, in as much the front–panel display and LCD controller is usually built on a separate panel of it's own in this type of set, so you should see 8 or so connections connecting it to the rest of the set, and one of these will be the micro's power–supply point! Have a good peer at it and get back with good clear pictures if you're still stuck! Chris Williams __________________ It's an enigma, that's what it is! This thing's not fixed because it doesn't want to be fixed!

1st Oct 2018, 12:28 pm	#7
DaniTDS Diode Join Date: Jun 2016 Location: Pontevedra, Spain Posts: 8	Re: Blaupunkt SQR 88 Woodstock not displaying a thing! Hi Chris, thank you! I'll try to get some photos. Almost all the circuitry is on the same PCB, except the final stage section which is a block you can take away (it has a fan!) and the front buttons. The LCD is connected to the main PCB through two flat multipin buses. The LCD controller is a PCF8576. About voltage regulators, at the start of the voltage input path there is a L4916 8.5V regulator I think, and a L498 which I cannot identify. Maybe I should start testing its output. Regards