HITACHI TV

[CAWORK]

I have a hitachi colour TV which stopped working a few weeks back.

When you turn it on it just makes a slight buzz and then it is totally silent-no picture/raster of any sort, no sound, electron gun not lit up etc.

I have had training in TV repair (aware of dangers etc) but not much experience so would appreciate just a bit of help.

I turned it on with the back removed and the very slight buzz I mentioned sounds like it comes from the power supply area.

Any help appreciated

Many thanks.

 

[tockworth]

what model is your tv and approx how old, widescreen, or 4:3

 

[Igorian]

Without seeing it, it's impossible to be precise. From what you are saying, it's possibly a dry joint in the PSU, which is quite common. Magnifying glass at the ready.

 

[CAWORK]

The set is conventional CRT 4:3.

If it is a dry joint then I'll have a go but I wont if it anything too difficult/expensive as the set is probably 20+ years old.

I'll get back to you regarding model no. etc

 

[tockworth]

yes give me the tube size and the model number. If its the chassis I am thinking of I may be able to pinpoint were the dry joint may be.

 

[CAWORK]

The tube size is 20 inch (51 cm)

The model number is CPT 2074

The serial number is U7BO19239.

Hope this helps.

 

[tockworth]

No this tv is older than I guessed it would be. The chassis that I am thinking of which was used in a lot of Hitachi tv's and the one that was prone to dry joints was not out when your t.v. was manufactured. To identify this chassis, with the back off looking into the tv there is a long metal heat sink runs up and down nearly the length of the chassis and it has four or five transistors attached at various points on this heat sink.These were the transistors which went dry joint to cause the symptoms you have. in Particular transistor marked ic950 was the favourite but transistors ic951 ic952 also were known to go dry.