For sale bare boards for Delta Pulse/Sniffer XR-71

[dbanner]

It is time for redesign of Delta for use of NE5534 or some other chip in front end of circuit, and put lf357 to its graveyard. Too many fake chips of especially lf357.

[dbanner]

Here we are. The national semiconductor sign looks a bit strange. Is there a way to test these ic's on a bench?

The original national semiconductors chip has a stripe on it. Texas instruments acquired national semiconductors in 2011, since then not sure about the appearance. So your chip look suspicious.
As far as testing, sheesh!

[dbanner]

Here we are. The national semiconductor sign looks a bit strange. Is there a way to test these ic's on a bench?

The original national semiconductors chip has a stripe on it.

[nonkapo]

Here we are. The national semiconductor sign looks a bit strange. Is there a way to test these ic's on a bench?

[kt315]

2.2k hanging on one leg, negative rail would be affected? Tip 127 hot? Output cannot swing negative, distortion results? Just thinking aloud.

sub was with constant low frequency loud hum. after i disconnected speaker i measured output voltage, it was DC +21V. Q6 was got very hot,
also whole heatsink of positive rail.
still did not see preamp board, maybe disbalance of voltage influenced afar.

[kt315]

I have another question. What is the rating/ specs of the actual speaker ( Wattage, Impedance) in the cabinet? My guess would be 8ohms/ ?watts.

on label of the speaker noted 4 Ohm =)

[dbanner]

2.2k hanging on one leg, negative rail would be affected? Tip 127 hot? Output cannot swing negative, distortion results? Just thinking aloud.

[dbanner]

I have another question. What is the rating/ specs of the actual speaker ( Wattage, Impedance) in the cabinet? My guess would be 8ohms/ ?watts.

[dbanner]

hi DB

nice question. it is RV8 on schematic and yes both parts on QV1 QV2 are stabilizer for +15V and -15V output.
it used like a supply for another board with filters.
just now i see full picture.

Complimentary Darlingtons, ha ha. Now we can see full picture. Thanks.

[kt315]

hi DB

nice question. it is RV8 on schematic and yes both parts on QV1 QV2 are stabilizer for +15V and -15V output.
it used like a supply for another board with filters.
just now i see full picture.

[dbanner]

ok K777. will do some pics later. charging all time by the amplifier... takes me much time. this female had took a part of my life
refused to share the schematic (((

http://ipic.su/img/img7/fs/thebox.1534963963.jpg

http://ipic.su/img/img7/fs/Untitled-1.1534964363.jpg

Hi KT, where is the 2.2k resistor on schematic? The one from the pic that you posted.

[dbanner]

Hi KT, where is the 2.2k resistor on schematic? The one from the pic that you posted.

[keith777]

ok K777. will do some pics later. charging all time by the amplifier... takes me much time. this female had took a part of my life
refused to share the schematic (((

http://ipic.su/img/img7/fs/thebox.1534963963.jpg

http://ipic.su/img/img7/fs/Untitled-1.1534964363.jpg

....Kt

also nice one nonkapo. best of look.

[nonkapo]

As noone reply on my post for LF357 i source them from Bulgarian online shop. How genuine they are is early to say, so will let you know once the machine is running. For now will try to share photo so the experts can say their word. The price was around 3 euro.

[kt315]

ok K777. will do some pics later. charging all time by the amplifier... takes me much time. this female had took a part of my life
refused to share the schematic (((

http://ipic.su/img/img7/fs/thebox.1534963963.jpg

http://ipic.su/img/img7/fs/Untitled-1.1534964363.jpg