Ancora sul mirabolante tuner Sony XDR F1HD. Come ho già scritto Claudio Re, ingegnere capo del network di Radio Maria World Family, si è dimostrato un vero amico modificando il mio tuner. Così adesso è alimentato a 12 V e posso usarlo in automobile quando vado su per i colli lungo la costa toscana o ligure a fare supertropo e, sole permettendo, ES. A casa invece lo alimento con un trasformatore portatile, tipo quelli per laptop, da 3 A che mi ha fornito Claudio (senza pià la seccatura del trasformatore 220-110 V necessario in quanto il Sony è made for Usa. Il tuner assorbe circa 1,1 A. Scalda abbastanza e per questo Claudio ha inserito anche una piccola ventola, di quelle che si usano nei PC.
Già alcuni amici mi hanno chiesto informazioni sulla modifica. Claudio mi ha mandato le indicazioni, che riporto di sotto, in Inglese... siamo international noi, Maremma bischera.
I received from Giampiero Bernardini a Sony XDR F1HD to modify at 220 V AC and 12 Vcc for portable use.
This receiver is based on the NXP chipset technology .
1) TEF6730 as AM-FM ( MW and Band II ) Tuner (see fig. 1)
2) SAF7730 as DSP IF demodulator
3) SAF3550 as HD (IBOC) Decoder
(fig.1 clic on the image to enlarge)Several instrumental good tests and practical receiving test on the field have been made from many other with amazing results. The reason is the use of all digital DSP demodulation and filtering from the SAF7730.
Scope of this document is to modify the receiver to allow 220 V AC and 12 Vcc for portable use. There are two rectified and not stabilized voltage inside the receiver: 10.5 and 5.2 V.
This is written on the transformer and rectifier board that I removed. 10.5 V consumption was measured to be around 100mA m while the 5.2 V was around 1000mA.
I was able, but not keen to put some switching regulators inside the receiver. I put instead two monolitic regulators using part of the internal heatsink that I enlarged in surface and a second heatsink.
Powering with 12 V with 1.1 A mean that all the receiver is dissipating heat in excess of 13 W. I added a little PC fan , fixed with silicon glue. I used a commercial 12 V 2.5 A switching power supply outside of the receiver with a jack .
The electrical drawing is shown in figure 2.
(fig.2 clic on the image to enlarge)In figure 3 the receiver is shown with all the modifications in place.
(fig.3 clic on the image to enlarge)Sorry for this “butcher“ work , description and informations but I didn’t have much time to devote to this work .
73-Claudio Re
I1RFQ
Turin
