Apex DT250A Digital Converter Box. I have almost no audio

[ivtec]

I have a Apex DT250A Digital Converter Box. I have almost no audio. If I turn up the volume on the box to max and the volume on the TV to max then I can hear the audio very faintly.

The picture is great and closed captioning works great.

To make sure it is not a TV/cable problem I swapped the cables from the DTV converter with that of the DVD player and still no audio. Used the same cable with the DVD player to the same inputs on the TV and I have audio. So it is not the TV or the cable. -

Here some pic any advice where to check? thanks

[ivtec]

Re: Apex DT250A Digital Converter Box. I have almost no audio

Hi guys; i had this Ota converter box in my scrap and the issue is sound is too low ,could it be this Chip be bad D4558?http://www.powermos.com/Uploads/download/D4558-40V SPEC Simplication.pdf

[petehall347]

Re: Apex DT250A Digital Converter Box. I have almost no audio

it could be that or power supply .best check supply voltages first then trace the signals

[ivtec]

Re: Apex DT250A Digital Converter Box. I have almost no audio

it could be that or power supply .best check supply voltages first then trace the signals

Thanks mate; the only thing wrong with this box the sound is low, in order to hear sound volume on the box it has to be max and max on the TV also . and the low sound is same on RF Coaxial 0r R L RCA cables , video is fine and all other functions are good.

[diif]

Re: Apex DT250A Digital Converter Box. I have almost no audio

What voltage do you get on pin 8 ?

[stj]

Re: Apex DT250A Digital Converter Box. I have almost no audio

those 4558's can fail - i'v replaced some in harmon-cardon speakers

[redwire]

Re: Apex DT250A Digital Converter Box. I have almost no audio

I wonder if it has a muting circuit, I would follow the RCA jack outputs back to the 4558. Have to see pic around Q19.

[ivtec]

Re: Apex DT250A Digital Converter Box. I have almost no audio

HI folks thanks for helping; ok i tested U4 and Q19 and results are in pic; also i have another Apex same model# and swapped the Power Sup and same result,also the mute is ok,the sound is audible mut has to all the way up on the box and on the TV,thanks again and have a Happy New Year

[petehall347]

Re: Apex DT250A Digital Converter Box. I have almost no audio

pin 8 is vcc .

[petehall347]

Re: Apex DT250A Digital Converter Box. I have almost no audio

should be something like 12v at pin 8

[budm]

Re: Apex DT250A Digital Converter Box. I have almost no audio

Are you sure that IC4 (4558 close to the RCA jacks) pin 8 has 0 V? Since you have a second unit, do you get the same reading on the working unit.
4558: https://cdn.badcaps-static.com/pdfs/...ba96f903cd.pdf
Is pin 4 actually connected circuit GND?

[ivtec]

Re: Apex DT250A Digital Converter Box. I have almost no audio

Are you sure that IC4 (4558 close to the RCA jacks) pin 8 has 0 V? Since you have a second unit, do you get the same reading on the working unit.
4558: https://cdn.badcaps-static.com/pdfs/...ba96f903cd.pdf
Is pin 4 actually connected circuit GND?

Thanks budm;Ok those measurements were taken with ground from tunner,now i went to take measurements again but now i used pin 4 as ground and pin 8 and i have 4.8 volts DC.

[budm]

Re: Apex DT250A Digital Converter Box. I have almost no audio

How about Q19 measurement with ref to circuit GND?

[ivtec]

Re: Apex DT250A Digital Converter Box. I have almost no audio

How about Q19 measurement with ref to circuit GND?

thanks budm ; tested Q19 with ota antenna connected see pic

[budm]

Re: Apex DT250A Digital Converter Box. I have almost no audio

So Emitter and Base pins shows 0V which means the Transistor is OFF, the Collector shows only 1.3V; need to find out what the Collector is connected to.
How about on the working unit, what Voltages do you get compared to this failed unit?

[ivtec]

Re: Apex DT250A Digital Converter Box. I have almost no audio

So Emitter and Base pins shows 0V which means the Transistor is OFF, the Collector shows only 1.3V; need to find out what the Collector is connected to.
How about on the working unit, what Voltages do you get compared to this failed unit?

Thanks budm; i already did text voltages on the other box that has the right sound and i don't see anything different,well i think i'm going to leave it alone and keep it for power supp part because i have 2 other boxes but they are Zenith and i like this one better,i only use this type of box to have Ota all over my house through coaxial cable ,thanks for trying to help