Hex Schmitt Trigger

[ivconic]

"...MC14584B Hex Schmitt Trigger is constructed with MOS P–channel and N–channel enhancement mode devices in a single monolithic structure..."

I am considering White's TM-808 and some modifications. I'm curious what other, easier to get, maybe more "modern" circuit could adequately replace this?

[Carl-NC]

Any other hex Schmitt inverter? There are several in the 4000 and 7400 series.

[Altra]

Not familiar with the TM808 circuit, The MC14584 can be replaced using a CD40106. Same pin out

[ivconic]

[ivconic]

Just finished a tedious service of one TM-808, came in hard condition, previous "meister" busted it totally up!
Not only that: he dismantled the TX&RX setup and simply pushed those small pcbs in a tubes without providing that antenna goes through the toroidal coil !???
Simply just "hided" them deep in a stem tubes!
Expecting to work like that... a magic!
...
Long story short; I fixed it and it is working quite alright. No problems at all.
Compared it with my previously made TF900 and can't notice significant differences in performances.
Yet... I am the man of many "complications"; I like to make my life complicated!
So I have a desire to make a copy of this one too.
4 things I will like to change here:
1) 78S40 although it still can be obtained in local stores; I would like to replace that part. It is adjusted to provide 15V single supply, later divided by half with "virtual ground" trick... as on many White's.
I would use LiPo 3.7-4.2 high capacity battery and dc/dc stepup from one of those modern ones.
2) Famous White's multi-switch, can not be obtained, so I will use rotary 4x3 switch instead.
3) Audio is boring, carrying so few information.
VCO, variable pitch and volume related to strength of a signal/detection.
4) Replace 4024 with 4040 and use available crystal.
Probably draw more compact pcb, omit few redundant components etc.
Interesting. I will put it on my "todo list" for the near future.
Not 100% sure that I will do it, yet... it will wait on the list.