Car Radio Blaupunkt 3030RDS/Citreon PH1(C)
 

Hi,

Need the schematic for the above car radio which is
fitted to my Citreon Xantia. Any pointers to a manual
vendor or other source would be appreciated.

The fault is a straightforward lack of sensitivity on FM
(not enough signal to hard limit) but a schematic would be
nice. Works OK on LW/MW so it isn't the antenna.


Cheers - Joe

Car Radio Blaupunkt 3030RDS/Citreon PH1(C)
 

Maybe this will help - but only if You have reception - only few strong
signals.

I have no schematic, but it looks something like this ...
Look in tuner for BA885 PIN diode (SMD). It is connected directly to HF
input from antenna - to the input filter.
Purpose is that for really strong signals this diode conducts towards HF
ground and protects gate of input HF ampli MOSFET (also SMD).
DC signal which makes this diode conducting, comes from IF system.
IF system supplies 8V for all normal signals - transistor BC858 not
conducting and diode not conducting.
Over ~80 dbuV IF supplies less then 8V which makes transistor and diode
conducting.
Sometimes this diode is bad, and sometimes You can measure more than 0V on
anode for all signals. Then it's probably SMD transistor BC858.
If this doesn't solve problem, check BF999.

If You have no signal at all, then it's something else...

To see the schematic use fixed width font (courier):

O +8V supply
|
|
e \| BC858 (pnp)
|-------------o DC signal from IF (8V for normal signal)
c /| b
|
|
|
|
-
| | R
| |
| |
| |
-
|
|________
| |
BA885 _|_ --- 1nF
PIN \ / ---
__V__ |
| | |
HF input | --- |------ to the mixer
| |
|| | |--
O__||__________|______________| input amplifier (BF999)
|| | | |--
/ | |
\ | |
L / --- |
\ ---
/ | (varicap)
\ |
| |
|_____|
|
---

Car Radio Blaupunkt 3030RDS/Citreon PH1(C)
 

Thanks Zeljko

I have replied to you by email.

Cheers - Joe