The Delco UX1 radio cassette I have (Blaupunkt 4-button cassette unit) needs a new optical sensor.



When it doesn't work properly it looks like motor has stopped to the "brains" of the unit.
The unit then thinks it's reached the end of tape and reverses back and forth before ejecting tape.
The part from Blaupunkt is not easy to find.

But here is a way to test and repair it.



The Blaupunkt unit schematics/wiring diagrams shown are here:
https://www.radiomuseum.org...r_23_7642888170.html

Of course, Honeywell discontinued part number HCL1395 a couple of years ago, so hard to find.

Reading through the comments under the video, it's apparent that Everlight ITR20904 also works.
https://www.alldatasheet.co...RLIGHT/ITR20904.html

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[This message has been edited by fierosound (edited 05-15-2022).]

More DIY on the cassette mechanisms.
http://www.gnttype.org/tech...ges/tape_player.html
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Cassette drive belts...
GM/Delco Autosound Cassette Players 1980 thru mid-1990's made in 4 styles.
(1) Non-auto reverse models use SBX7.4
(2) Auto reverse Fijitsu 3 (Mechanical) Button Mechanisms use SBS8.6
(3) Auto reverse Blaupunkt 4-button Mechanisms use 2 belts: AV-SBS4.9 & AV-SBS9.2
(4)Pioneer (88 up) and Alpine Mechanisms (91 up) have electronic switch buttons SBS9.2
http://kenselectronics.com/lists/belts.htm#Auto

On Blaupunkt units, the Pulse Generator Disk (Delco PN 1226632) is sometimes the culprit.
https://www.ebay.com/itm/De...ng-Disc/124095797548

[This message has been edited by fierosound (edited 09-04-2020).]

Here's a Delco item that looks like it is the correct part (but shipping to Canada is ridiculous)

GM Delco 90-95 Type D 2000 Series Cassette Deck Light Sensor Assy 1229219 NIB
https://www.ebay.com/itm/GM...19-NIB-/262385753000

[This message has been edited by fierosound (edited 05-15-2022).]

Not that it couldn't fail, but i've never had to replace that part. In my experience diagnosing the scenario you described, i've always found a broken drive belt. Push the tape in, the unit switches direction and ejects the tape.

quote Originally posted by donuteater306: Not that it couldn't fail, but i've never had to replace that part. In my experience diagnosing the scenario you described, i've always found a broken drive belt. Push the tape in, the unit switches direction and ejects the tape.

Mine is apart and has no broken belts.
It runs perfectly fine when I shine a light on the sensor assembly.
So the IR light in the thing is shot.

[This message has been edited by fierosound (edited 09-07-2020).]

quote Originally posted by fierosound: Mine is apart and has no broken belts. It runs perfectly fine when I shine a light on the sensor assembly. So the IR light in the thing is shot.

Interesting...good catch.

quote Originally posted by fierosound: Mine is apart and has no broken belts. It runs perfectly fine when I shine a light on the sensor assembly. So the IR light in the thing is shot.

quote Originally posted by donuteater306: Interesting...good catch.

Did the same test as in the YouTube video posted above.

quote Originally posted by fierosound: Here's a Delco item that looks like it is the correct part (but shipping to Canada is ridiculous) GM Delco 90-95 Type D 2000 Series Cassette Deck Light Sensor Assy 1229219 NIB https://www.ebay.com/itm/GM...19-NIB-/262385753000

Delco radio cassette fixed!
Above part is correct for our Delco radios with Blaupunkt cassette units.



New sensor is on right with "ribbon cable" instead of separate wires and is identical.
Repair was done as per video in first post.



Sensor snaps into unit exactly as it should.



Biggest part of job is removing old sensor and fishing new wires through and soldering them.
This new sensor wiring had a clip on the end that wasn't needed and was cut off.

Red-Yellow-Green
becomes
White-Yellow-White/Red stripe (new sensor)



Success! Cassette plays great!
AutoReverse, FF, REW, Eject and Power Off Eject all work properly.



Only now I discover this is one of those radios where the clock won't shut off when power is turned off (thus draining battery).
But I see some people have found a fix for that (replace transistor).

[This message has been edited by fierosound (edited 09-26-2020).]

quote Originally posted by fierosound: Only now I discover this is one of those radios where the clock won't shut off when power is turned off (thus draining battery). But I see some people have found a fix for that (replace transistor) .

Getting some NTE232/ECG232 transistors from
https://www.nettyelectronics.com/
Only $2.00 1st Class Mailing in Canada! He's a hobbyist.
One electronics place was US$15.85 for shipping, another wanted a US$10 fee for "paperwork" + shipping.

Here's repair directions with pictures to replace NTE232 transistor to fix "clock always on" problem.
http://garageledlights.com/.../body_radio_fix.html

[This message has been edited by fierosound (edited 09-26-2020).]

Delco Radio Service Manuals (listing starts with year... 1984 etc.)
Place also has some Delco radio parts and new faceplates.

You'd have to look at the cover page of the Manuals for applications and radio Part Number you have - Pontiac P is Fiero
http://elliottscarradio.com...ll-kinds.html?page=6

Service Manual for the radio/cassette in FIRST post of this thread would be for UX1 Part Number 16050352
http://elliottscarradio.com...e-manual-p17419.html

See Radio RPO codes on fender decal and reference that to Pontiac part number.



From P22 Parts Book

1984 (radios had black faceplate and knobs)
Part number, description and RPO code
16033472 Receiver, radio w/Mono UL6
16033592 Receiver, radio w/Mono U63
16030042 Receiver, radio w/Stereo UL1
16030052 Receiver, radio w/Stereo UU7
16032452 Receiver, radio w/Stereo UU6
16034222 Receiver, radio w/Stereo UU9

1985
Part number, description and RPO code
16035102 Receiver, radio w/Stereo UX1
16035122 Receiver, radio w/Stereo UL1 (except Seek/Scan)
16036912 Receiver, radio w/Stereo UT4
16040862 Receiver, radio w/Stereo UM6
16048312 Receiver, radio w/Stereo UM7 with Seek/Scan

1986-88
Part number, description and RPO code
16048312 Receiver, radio w/Stereo UM7 with Seek/Scan
16050352 Receiver, radio w/Stereo UX1
16050362 Receiver, radio w/Stereo UT4
16040862 Receiver, radio w/Stereo UM6

16041072 Speaker, front, 5-1/4" 4-ohm round subwoofer UQ6
16040752 Amplifier, low freq audio - comes with UQ6 option

This is the Service Manual for the Subwoofer Amplifier PN 16040752
http://elliottscarradio.com...-service-manual.html

[This message has been edited by fierosound (edited 09-26-2020).]

quote Originally posted by fierosound: Delco Radio Service Manuals (listing starts with year... 1984 etc.) Place also has some Delco radio parts and new faceplates.

Thanks for this. I've been looking for a source for manuals like this for years.

quote Originally posted by Raydar: Thanks for this. I've been looking for a source for manuals like this for years.

I currently have my UX1 apart for a deep clean, do you know of any pots or something on the cassette mech that might adjust tape speed? Mine plays a little fast and I've never found a fix for this.

[This message has been edited by jonrev (edited 04-20-2021).]

85 GT. When I put in a tape it goes to "fast forward" Any suggestions?
Thanks

More radio repair threads:
https://www.thirdgen.org/fo...k-speed-trouble.html
https://www.thirdgen.org/fo...-repair-options.html

Also see this.

quote Originally posted by jonrev: I currently have my UX1 apart for a deep clean, do you know of any pots or something on the cassette mech that might adjust tape speed? Mine plays a little fast and I've never found a fix for this.

quote Originally posted by jonrev: Welp I just answered my own question... bastard speed adjusting pot eluded me for years, turns out it's on the cassette mechanism board and hidden by the lower metal plate which guards the belts. I took a Dremel to the plate so I could turn it with the radio plugged back in. All good.

Just a note about the ITR20904 replacement for the optical sensor. It works, but pins 1 and 3 are reversed.