452
Item nr.


Paeansonic 210SP Pocket radio

Pocket construction kit.


Data for Paeansonic 210SP
ProductionThe Netherlands, 2016.
Price was 4.01€.
BandsMW (525-1605kHz), TV/FM (76-108MHz).
Semi-
conductors
CD9088 (FM tuner), TA7642 (AM tuner), TDA2822M (AF amp), LED.
CabinetPlastic. Size 10x6,5x2,5cm. Weight 73gr.
PowerBatt 2xAA.
DocumentsSchema.

The Design

This radio combines a very modern and a very classical design. The AM reception is Tuned Radio Frequent, while the FM reception uses a very low IF of 70kHz, so I presume the CD9088 includes a quadrature detector.

If you ever want to construct an AM receiver with the TA7642 IC, please take a look at the power supply of the 7642 here. The 7642 needs about 1.3V and draws 0.3mA, so one might be inclined to place a series resistor of 4k7 between the battery and the IC. Bad thing would be, that the entire series resistor would be "visible" for the AGC current flowing through the IC, resulting in an overly strong AGC operation. The ZN414 technical notes suggest a so-called "diode drive", where the supply voltage is kept constant by running excess current through conducting diodes. In that respect, this schema contains the diode drive, with the LED functioning as voltage stabilizer for the 7642.


Obtained3/2017 from Aliexpress.com.
Condition7.
DisposedScrapped 3/2021.
Sound samplePLAY SOUND   The quality of the receiver is very suitable for 19th century sounds.

This Object

I built one of these in March 2016 and another one in March 2017. Performance of this second one was quite bad, especially on AM. Which is unfortunate, because I built it as an illustration to a lecture on the TA7642 IC. After a week I found out that I had swapped two resistors (of 22k and 2k2), and reverting the resistors brought back normal (that is: quite poor) AM operation.

Part of Gerard's Radio Corner.
Generated by SiteBuilder on 26/2/2024 by Gerard (g.tel@uu.nl)