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Old 7th Feb 2019, 1:06 pm   #1
adamsomerset
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Default Blaupunkt Memphis SQR 88 Car Stereo.

Could anyone help please with a problem with my car stereo. After my car being in storage for 3 months, on restarting it I have found that the LCD display on the stereo is blank. The display was fairly dim before the car was put away and I think it only visibly displayed the wavelength and not other info. Having changed the car battery and hence disconnected the stereo I now can't re enter the radio code due to no display.

Any ideas please on what I could do in the way of checks or repairs or who may be able to help with a repair?

Many thanks, Adam.
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Old 7th Feb 2019, 3:34 pm   #2
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Default Re: Blaupunkt Memphis SQR 88 Car Stereo.

Although I used to be an I.C.E Service engineer for a Blaupunkt Main dealer, and remember the Memphis SQR88, I'm not certain why the LCD is blank-it could be a faulty display. If so a replacement will be almost impossible to source, because that model is now 30 years old, and long obsolete(The '88' indicates that it has 4 x 20 watt o/p {first 8}, and was introduced in 1988 {second 8} but it could also be a fault in the display driver circuitry, possibly due to bad electrolytic capacitors.
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Old 7th Feb 2019, 7:19 pm   #3
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Default Re: Blaupunkt Memphis SQR 88 Car Stereo.

Thanks for the info.
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Old 8th Feb 2019, 10:54 am   #4
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Default Re: Blaupunkt Memphis SQR 88 Car Stereo.

LCDs generally, and the ones in car radios in particular (because of the wide temperature and humidity range environment) can suffer from poor contact problems involving the conductive rubber trace strip that often interfaces between PCB tracks and LCD segment contacts as they age. A bit of careful and patient cleaning of contact surfaces can sometimes bring the display back (or most of it....) but it's often a short-term and frustrating exercise unfortunately. Don't know of your level of knowledge and experience, so excuse me if I'm teaching to suck eggs, but car radios are typically close-packed, tricky and delicate to dismantle and LCD glass is thin and fragile.

'LIVEWIRE?' is obviously the man to go to for this sort of thing, but I got the impression through "can you just look at this for me....."-type requests that the Bosch/Blaupunkt group stuff that was badged for various car makers' OEM fitment seemed more prone than most to LCD problems with age.
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Old 8th Feb 2019, 11:18 am   #5
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Default Re: Blaupunkt Memphis SQR 88 Car Stereo.

turretslug, you are partly correct in that a lot of Blaupunkt car radios & stereos were badged for, among others, Ford, Rover, BMW, etc., but the Memphis SQR88 was only sold by Blaupunkt Dealers, of which the firm for whom I worked between 1972 & 1995 was one. Somewhere I may still have the service manual for that model, among quite a lot of Blaupunkt manuals. You are also correct in that Car Stereos were/are close-packed with small and delicate components. In addition, Blaupunkt tended to use quite a few Hybrid Circuits made on thick-film substrates, which were exclusive to their products, and not replaceable by any open-market spare parts. Not a problem during their 'service life', since dealers could order these items as & when needed, but now that these stereos are 25-30 years old, as I noted, replacements are 'unobtanium'. I forgot about cleaning the contact strips of displays-a delicate job with no guarantee of success.
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Old 8th Feb 2019, 3:19 pm   #6
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Default Re: Blaupunkt Memphis SQR 88 Car Stereo.

Thanks for the suggestion, will see if I can clean the contacts, maybe there's nothing to lose.
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Old 8th Feb 2019, 11:38 pm   #7
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Default Re: Blaupunkt Memphis SQR 88 Car Stereo.

Didn't many of the car units of this era have a small 12 volt bulb that if blown renders the display blank? ISTR this more than once in the early 90's when car stereo's were on the bench for repair!
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Old 9th Feb 2019, 10:04 am   #8
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Default Re: Blaupunkt Memphis SQR 88 Car Stereo.

Some did, nickdoofah, but I can't recall whether the Memphis 88 series did have separate bulbs or not. It's a long time since I last saw one!
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Old 10th Feb 2019, 1:40 pm   #9
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Default Re: Blaupunkt Memphis SQR 88 Car Stereo.

Thanks for the suggestions. I cleaned the contacts but no joy. I checked the backlight bulbs, one below the LCD had blown but when fixed all it did was enable all the backlight bulbs to work, had no effect on the LCD operation.
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Old 10th Feb 2019, 2:06 pm   #10
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Default Re: Blaupunkt Memphis SQR 88 Car Stereo.

If you know the key sequences required to enter the unlock code, perhaps it's in the manual, you may be able to unlock the radio without the need for a display.
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Old 10th Feb 2019, 2:27 pm   #11
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Default Re: Blaupunkt Memphis SQR 88 Car Stereo.

Most Blaupunkt Car Stereos used a 4-digit code, which was entered by counting in the individual digits -i.e., if the code is 3768, pre-set button 1 is pressed repeatedly until '3' is displayed, button 2 until 7 is displayed, and so on. What I can't remember is whether the sequence as you press ech button goes '0.1.2.3.etc., or 1, 2, 3, etc. - not much help when the display isn't working, I know. There was also, on most models, a limit to the number of incorrect attempted entries before the system locked out permanently. In addition, some models required a 5th. button to be pressed to activate the radio once the correct code was entered, and some automatically unlocked without the need to do this. If I can find the Memphis SQR88 service manual, I'll be able to give a definite answer to this question, but it seems like the display has failed and this, because of the age of the set, will be irreplaceable.
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Old 10th Feb 2019, 3:24 pm   #12
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Default Re: Blaupunkt Memphis SQR 88 Car Stereo.

Is this now fixed ?
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Old 10th Feb 2019, 9:39 pm   #13
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Default Re: Blaupunkt Memphis SQR 88 Car Stereo.

Unfortunately not! Still looking for a solution. Might be helpful to see if a code can be entered without a display.
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Old 17th Feb 2019, 9:18 pm   #14
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Default Re: Blaupunkt Memphis SQR 88 Car Stereo.

I've had a good look through my Blaupunkt Service manuals (of which I have many dating from the 60s onward), and haven't found any for the Memphis 88 or the similar Kingston model, though I'm certain I have at least a circuit diagram & PCB layout diagram somewhere. If I find the document(s) I'll hopefully be able to post a definite answer to your questions, adamsomerset.
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Old 17th Feb 2019, 11:56 pm   #15
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Default Re: Blaupunkt Memphis SQR 88 Car Stereo.

I've had a look and I've found that I have the user manual for the SQR 88 and I've just scanned it - the instructions for entering codes are in the last two scans, with reference to the first scan pictorial.

Livewire - While we're on the subject of these stereos, and knowing what vehicles these radios were originally fitted in, you may possibly be the man to help me. I'm looking for the service manual for the infamous Grundig 4870 RDS which succeeded the Blaupunkt SQR 88. I've already got the user manual, but have never been able to locate the service manual and 'strangely' I've got a small collection of these sets and I'm down to only one that's in fully working order now. These were way ahead of their time nearly thirty years ago with a ten disc CD autochanger with long, medium, short and FM radio.

Scans below - hopefully...the last page (scan6) will have to be in the next post down:-
Attached Files
File Type: pdf Scan1.pdf (304.1 KB, 236 views)
File Type: pdf Scan2.pdf (369.4 KB, 183 views)
File Type: pdf Scan3.pdf (438.4 KB, 195 views)
File Type: pdf Scan4.pdf (409.9 KB, 184 views)
File Type: pdf Scan5.pdf (391.5 KB, 190 views)
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Old 17th Feb 2019, 11:58 pm   #16
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Default Re: Blaupunkt Memphis SQR 88 Car Stereo.

Last scan of the instructions for the SQR 88 below:-
Attached Files
File Type: pdf Scan6.pdf (300.0 KB, 204 views)
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Old 18th Feb 2019, 2:33 am   #17
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Default Re: Blaupunkt Memphis SQR 88 Car Stereo.

Well, I may be sorted!

Up late listening to Keith Skues and decided to go searching for a Grundig manual and happened to find a link to one for the Grundig 4870 suffix 'A' in an old post from a few years back on this very forum, so hopefully it should be what I'm looking for, regardless of the additional 'A' suffix. It shows how long it's been since I last looked for a manual because there was nothing whatsoever when I last did a search. This is the second time this has happened to me recently. A late 80s 'boombox' type stereo that used to be my radio at work which I found in the skip and used to stand on the window ledge and provide the background music, news etc., in my work room/office for quite a few years, and came home with me when I finished. It ran as a kitchen radio for several weeks and then packed up on FM. I looked for a service manual at the time but I found that there was nothing out there, so I shoved it up in the loft where it's been for over four years until I found it again a couple of weeks ago. After coming down from the freezing loft it worked perfectly for a fair while and then packed up again. I decided to have a go at fixing it and reckoned that the fault was likely to be in the first RF amplifier stages of the FM tuner. Working blind I narrowed down to what I thought were a couple of transistors in this stage and accurate use of freezer singled out one of them. It was at this stage that I thought of having another look for the service manual on line and this time it was available, obviously kindly uploaded by someone since I last looked. However, what the manual showed me was that what I had thought were transistors were in fact two varicap diodes back to back in a single package. To cut a long story short, I'd basically found the fault first, then looked for the circuit diagram afterwards, not expecting to find it. The end of the story (so far) is that after a bit of manipulation with pliers, the device started working, and yes, I did check and re-solder any possible dry joints, but it was the device itself that was at fault. This is the radio that I've just been listening to Keith Skues on - if it does eventually play up again then I'll perhaps start a thread on it as there's only a manufacturers part number in the manual relating to the other of the two double varactors, as due to a mistake in the printing of the parts list (typical!), the faulty part isn't listed, but i would guess that it's exactly the same as the other one that is listed, however, a question for a separate thread, I think.
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Old 18th Feb 2019, 9:49 am   #18
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Default Re: Blaupunkt Memphis SQR 88 Car Stereo.

Thanks for those links to the Memhis SQR88, Techman. Hopefully they'll help the OP (adamsomerset) solve the problem with his stereo, although entering a code without a functioning display can be difficult. In the past I've manged to do it with some of the Grundig car stereos where the only display was separate from the main unit. I'd forgotten that the Memphis also had the facility to enter the vehicle registration as well, b.t.w.
Glad you found the Grundig 4870 manual, as I know I only have two of their service manuals, neither for that model. I have heaps of Blaupunkt and quite a lot of Clation Manuals, plus some Lucas Audio, Motorola, Philips, etc., ones because the firm for whom I worked were agents for all those brands, and I kept a lot of the service manuals after they closed down in 1995.
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Old 18th Feb 2019, 2:42 pm   #19
adamsomerset
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Default Re: Blaupunkt Memphis SQR 88 Car Stereo.

Thanks for the links to the owners manual. I had already tried what I thought was the correct procedure but failed to succeed. Will try again, but can you tell me with the codes whether 0 was an available code number or would it be from 1 to 9? This affects what I do, working blind, from the point of view of how many times I press the buttons. I have probably used up my first 4 attempts, so presumably have to leave set on for an hour to try again.
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Old 18th Feb 2019, 6:38 pm   #20
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Default Re: Blaupunkt Memphis SQR 88 Car Stereo.

You have to leave the stereo powered up and switched on for an hour certainly, but I don't remember if '0' was included in the codes for the Memphis, though '0' was used in other Blaupunkt models of the same era.
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