Magnavox F8 chassis model TS2774
(Revised 7-26-99)
DEAD, horizontal output leads broken
NAUD, IAUD, resistor network broken


We have seen lots of these in the shop and, so far, there is little service information. All service data is currently on CD-ROM. As more information becomes available, Iíll pass it on. What I do have are some part numbers, which may come in handy. The horizontal output transistor on this unit was apparently subjected to excessive

lead forming and minute flexing of the heatsink during transportation. Either way, the leads end up fatiguing and breaking causing an intermittent dead or dead set. The pictures above shows the transistor that separates itself from the board. It should be noted there is a large clamp covering the transistor which tends to hide it from view.

In order for these not to be back in for service, the components must be checked and if the leads are weakened the component must be replaced. NOT RESOLDERED.  Resoldering will only temporarily repair the problem.
 

This Just in: 7-27-99........

The first four parts listed, 7460, 3607, 7950, and 7401 are prone to having cracked or broken leads due to mechanical fatigue. The resistor pack, 3607, is particularly hard to diagnose because you would not likely make the connection between this part, which is in system control, and the audio circuit. In the absence of having a schematic, I can only guess that it is in the mute or volume control circuit. It is located right next to pin 1 of the microprocessor, 7600.

Location Part Number  Description PCB coordinates

7460  9340 170 50127 Horizontal output transistor .......A-6
3607  4835 111 97046 Inline resistor pack  ..................C-2
3607  4835 111 97048 (alt) Inline res pack (extra legs) ...C-2
7950  4835 209 88543 Audio IC TDA70571Q/N2........ E-5
7401  9322 121 47687 Vert out STV9379F  .................C-8
7250  9352 620 26112 IC, Jungle  .............................. D-6
1000  2422 542 90049 Tuner    ...................................E-7/8
7330  9352 184 10112 Video output IC ...................... CRT-pcb

Please give me feedback on this unit. If you have any experience you want to share on this unit please pass it on to me via E-mail or contact me me at 0582 extension 1105.

Thanks to Craig Bell for the compiling of this document.

Dennis Viereck