HU-850 radio fault - Page 3

john493 · Oct 24th, 2022, 13:28

Quote:

Originally Posted by ma70

Not the amp, it's the head unit itself. I'm currently working on ours & having reflowed a few joints with semi-success I'm now in the process of sourcing/replacing a pair of transistors and a voltage regulator which I believe to be the cause of this problem.

The affected area of the board is next to the tuner can & the parts I suspect are Q938/Q939 and IC945 (D1760Q transistors and an ST LF33A 3.3v regulator respectively, all in a DPAK package).

These parts are available cheaply off ebay & even with my inappropriate soldering gear I hope to make a repair.

Even if you can't/wont go into the stereo yourself, at least you could advise any repairer what the problem is likely to be.

Any ideas where I can get a wiring diagram for the HU-850 head unit ?

john493 · Nov 10th, 2022, 13:47

Got an HU-850 in my 2006 V70 - no sound when radio selected, it does a channel scan but doesn't find any channels. CD player works OK, so I'm assuming a fault with the aerial or the AM/FM tuner.

Wondering if I've got a problem with the aerial - I think the aerial is built into the boot side window ?

Anyone know if there's an aerial amp or similar I should be looking at ?

stuart bowes · Nov 10th, 2022, 13:53

Some info here might point in right direction

https://www.volvoforums.org.uk/showthread.php?t=201621#:~:text=The%20main%20ampli fier%20is%20on,well%20you'll%20see%20it.

Not sure how accurate this is because like you I was under the impression the aerial is stuck to the window maybe there are two of them or something

could also have been left out the back of head unit of course, if there's been any previous attempts to repair

Simmy · Nov 10th, 2022, 18:10

lead free solder is the problem with most automotive electrical faults. radios /ecus /dims/ bcm s and many more .volvo diagnostics make a living out of repairing these solder problems. there should be more company's doing this kind of work

john493 · Nov 10th, 2022, 21:27

I need to check out the aerial amplifier - I've read it's sometimes in the rear bumper but pretty sure that's not where it is on my car - the actual aerial is in the boot window I believe.
Any ideas where I can find the amp - I think it's a green box ?
Thanks

Nov 10th, 2022, 13:47	#22
john493 Spannering since birth Last Online: Apr 27th, 2024 21:26 Join Date: Jul 2006 Location: North Oxon	HU-850 radio not working Got an HU-850 in my 2006 V70 - no sound when radio selected, it does a channel scan but doesn't find any channels. CD player works OK, so I'm assuming a fault with the aerial or the AM/FM tuner. Wondering if I've got a problem with the aerial - I think the aerial is built into the boot side window ? Anyone know if there's an aerial amp or similar I should be looking at ? __________________ V70 D5 eu4 manual M66 2006 > XC90 brake conversion, stage 2 VDASH remap. BMW R1200GS BMW R1100GS (GS Addict)

Nov 10th, 2022, 13:53	#23
stuart bowes trying to be helpful Last Online: Today 17:11 Join Date: Aug 2020 Location: Dagenham	Some info here might point in right direction https://www.volvoforums.org.uk/showthread.php?t=201621#:~:text=The%20main%20ampli fier%20is%20on,well%20you'll%20see%20it. Not sure how accurate this is because like you I was under the impression the aerial is stuck to the window maybe there are two of them or something could also have been left out the back of head unit of course, if there's been any previous attempts to repair __________________ V70 '01 auto petrol 2.4 (140) 70k ------------------------- mini project - link Last edited by stuart bowes; Nov 10th, 2022 at 14:09.

Nov 10th, 2022, 21:27	#25
john493 Spannering since birth Last Online: Apr 27th, 2024 21:26 Join Date: Jul 2006 Location: North Oxon	I need to check out the aerial amplifier - I've read it's sometimes in the rear bumper but pretty sure that's not where it is on my car - the actual aerial is in the boot window I believe. Any ideas where I can find the amp - I think it's a green box ? Thanks __________________ V70 D5 eu4 manual M66 2006 > XC90 brake conversion, stage 2 VDASH remap. BMW R1200GS BMW R1100GS (GS Addict)

Nov 10th, 2022, 18:10	#24
Simmy Premier Member Last Online: Today 20:39 Join Date: Mar 2017 Location: Manchester	lead free solder is the problem with most automotive electrical faults. radios /ecus /dims/ bcm s and many more .volvo diagnostics make a living out of repairing these solder problems. there should be more company's doing this kind of work

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