hello and congratulations for the work done on this benson.I wanted to ask if this scheme was verified as I believe there is some error, i.e .:
1) the operational rc4558 pins 5,6,7 are not listed in the diagram
2) the cooling resistors of transistor 2n5191G in the diagram are listed as 68R 1 / 2W while in the image below you say they are 68k 1 / 2w (which are they really?).
3) under the 1k trimmer there is written 757R on the tested unit What does this mean?
4) There is no + 9v connection listed but only V + references, where do we start with a + 9v connection? it is assumed that a connection could be applied on the reference v + on the diode 1n400x ????
thank you for the answers you will give us
Thanks for spotting the error with the heater value. I corrected the layout posted above,
The 4558 is a dual opamp. The schematic lists 1/2 RC4558. That means only one op-amp of the dual package is used and as such the nonlisted pins where not used. My layout uses a TL071 as it's a single op-amp and the pinout is slightly different. Download and compare the two different datasheets and you will see the differences and similarities between the two.
757R means the trimmer was adjusted to 757Ω (ohms) resistance. The two symbols Ω and R are interchangeable and mean the same thing.
hello should this be the correct schematic? I circled the connections for the 9v in purple and the other part of the opamp pin 5/6/7 in red. as a scheme, and if you want you can also post it on the page.