How to detect IC fm receiver was broken?

Thread Starter

purwadijokow

Joined Sep 21, 2020
4
Hello everyone, it's my first thread here. I build fm radio receiver, use fm receiver chip (IC) CD9088 similar TDA7088 chip, and can not recieve broadcast fm station. I guess if the ic was broken, how to know or how to detect or indicate if the ic was broken. May somebody can help me?
Sorry for poor english.

Soory for mistake in tittle, I mean "How to detect ic fm receiver was broken?"
Tank you.
 

Audioguru again

Joined Oct 21, 2019
2,055
Buy a "radio" with a real TDA7088 for $1.00 at The Dollar Store and compare its DC voltages with the cheap Chinese one you have. The IC is almost 30 years old and has VERY poor performance.

The Dollar Store cheap radio I have with a real TDA7088 is overloaded by strong local stations and does not pickup distant stations that my cheap clock radio receives.
 

Thread Starter

purwadijokow

Joined Sep 21, 2020
4
thank you. Now I get information from TDA 7088 datasheets, there is any voltage indicator on each pin, and i compare with Chinese chip, there are similar, but i dont know why Chinese Radio with CD8008 can not detect fm broadcast station.
 

Audioguru again

Joined Oct 21, 2019
2,055
You said you built the FM radio that does not work.
1) Did you build it with a printed circuit board that has a small correct size for the 100MHz circuit, or did you use a solderless breadboard that has too much capacitance between the row of contacts and has too much inductance in the wires all over the place? Or did you build the Elenco kit?
2) Did you use the correct values for its capacitors?
3) Did you use the correct values for its inductors?
4) Did you use the correct varicap?
5) What did you use for its audio amplifier?
 

Audioguru again

Joined Oct 21, 2019
2,055
When you buy no-name-brand cheap junk then you usually get cheap junk.
Maybe the instructions are wrong? Parts ion the wring place? A backwards diode?
 
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